This reverts commit 22738b1213fff704d288ec84976fa84ff9535aba.

   The command was added due to a lack of my understanding of how the pwm command can be used.

   The command is not needed as the all flag can be used or a proper
   mask WHIHOUT -g

   fmu task mode_pwm
   pwm rate -a -r 50 -d /dev/pwm_output0
   pwm arm
   pwm test -a -p 500

   fmu task mode_pwm
   pwm oneshot -a -d /dev/pwm_output0 is the same as pwm oneshot -m 0xff  -d /dev/pwm_output0
   pwm arm
   pwm test -a -p 500

 Since the Onshot<->PWM mode is changed based on rate. The
 this signale the higher layers that the operation is invalid

 test case:
   fmu task mode_pwm2cap2
   pwm oneshot -m 0xf -g 0 -d /dev/pwm_output0

   should fail, because all the channels in the group are
   not in the same mode.

  1) Updated copyright
  2) Defined BOARD overrideable BOARD_PWM_FREQ and BOARD_ONSHOT_FREQ
     Not recogmended but allow experimentation
  3) Solved the support for BOARD_PWM_DRIVE_ACTIVE_LOW using
     the Polarity control bits as apposed to the negation of
     the ARR.
  4) Added a cache for getting a timers channels. This is static
     and benifits from the qucik response.
  5) Added a function to realocate all channes in a given timer
     from one mode to another.
  6) Removed the frequecy table in favor of the intended use of the
     channel mode set. At it is the way to determine the mode of a
     channel. Or in onshot's case a timers's complete set channels.
  7) Added 2 lowlevel mode changing functions:
     io_timer_set_oneshot_mode and io_timer_set_PWM_mode
     that encapsalate the changes in mode to one place
     in the code.
  8) Added io_timer_trigger (the up_pwm_update) with low
     latancy timer to time in updating.
  9) io_timer_set_rate - use sets to enforce all or none
     rules for switching  PWM<->OneShot.
     Onshot is entered using the very approriate rate of 0.
     Only deltas will change the HW state.

   1) Define IOTimerChanMode_OneShot
   2) Added detailed commnent on .clock_freq and how it is used
   3) Added single additional API point in support of Onshot mode
      io_timer_trigger - That trigger all timer's channels in Oneshot
      mode to fire the oneshots with updated values.

   As discusssed in https://github.com/PX4/Firmware/pull/6678#discussion_r104177663
   this take the safe approach to only call up_pwm_update on a valid mix
   it does keep intatct the riginal author (OA) had an intent.

   1) Use up_pwm_retrigger to triger onshot
   2) Updated comment to explain why a rate of zero makes sense
      to set oneshot mode.
   3) Updated copyright

  1) Validate timer paramater before using it.
  2) Allow rate of 0 to enter Oneshot mode
     At first blush this seamed like a hack, but at Mark
     pointed out to me, Onshot PWM does not have a rate
     So this is a realy a clever and beautiful simplification
     on his part!
  3) Exposes up_pwm_update that runs io_timer_trigger
     Which trigger all timer's channels in Oneshot mode to
     fire the oneshots with updated values.

  This api will REWORD

  At at a period greater than the the max Oneshot pulse width
  Trigger all timer's channels in Oneshot mode to fire the
  oneshots with updated values.

   The fmu now support the commandline option to be run as a task
   or off a work queue.
   This reverts the board_config.h changes from commit
   e33af23122f5ee3030bb9745bbbf616b24c2a14a.

Conflicts:
	src/drivers/px4fmu/fmu.cpp

  The new optional option is
  fmu [task] ....

  fmu task mode_pwm - start fmu as a task
  fmu  mode_pwm     - start fmu as a worker

This reverts commit 30fe2aa4fb8c099028fd5ca4f50940e88eddbb08.

cleanup and remove unused (new) params

change fmu to task

increase fmu_servo task priority to max and enable true oneshot

use lowest FMU priority which minimizes jitter

constrain oneshot updates to control group 0 events

* Backport:stm32f7: stm32_allocateheap: allow use DTCM memory for heap

   Back port of upstrem contrib by Jussi Kivilinna <jussi.kivilinna@haltian.com>

   stm32f7: stm32_allocateheap: allow use DTCM memory for heap

   STM32F7 has up to 128KiB of DTCM memory that is currently left unused.

   This patch adds DTCM to main heap if CONFIG_STM32F7_DTCMEXCLUDE is not enabled.

* px4fmu-v5_default:Enable inclusion of the DTCM in the heap

  CONFIG_MM_REGIONS=3 adds the DTCM region to the heap.

depending on two altitudes that can get set as parameter
the logic linearly slows down from higher land altitude 1 to slower land altitude 2

mc_pos_control: reorder if statement

mc_pos_control:  add get function for cruising speed

mc_pos_control: move limit vel xy after velocity controller