2. Remove printf in the cpp

Add -D__DF_RPI in posix_rpi_common.cmake
Add rpi_rc_in and rpi_pca9685_pwm_out  driver in posix_rpi_common.cmake
Rename posix_rpi_cross_without_navio_or_pxfmini to posix_rpi_cross_no_shield.cmake

2. Rewrite and rebase pca9685 driver
3. Try to fix issue when push the stick of channel 3 to the maxmum position, 0uswill be output to channel 1, should be maxmum pwm signal
4. Fix the code style

Now I've fixed style of the code

Both 8 channels PPM encoder and 8 channels revicer are required.
Before launch px4, ppmdeocde programe should be launched.
To download ppmdecode programe,
visit https://github.com/crossa/raspberry-pi-px4firmware.
Pxfmini and navio are not popular autopilot hardware in china,
I can handly to purchase it.
So that I use raspberry pi to build autopilot separately.
This dirver help us to decode ppm single to pwm and pushlish it

Just update in RAM is enough.

Use the size of each item type instead of the biggest one.

In AeroFC that runs is constrained mode it was using 7860 bytes
and now it uses 6930 bytes almost 1KB less.

Check for the broadcast systemd id to block forward of broadcast
commands.

   This change first pushes out the _reset_wait by 100 Ms.
   which is about 3 time longer then the code take to execute.

   Then it does the reset of the accel, gyro and mag and
   the ends the wait by setting _reset_wait to now+10 us.

   The MPU9250 and MPU6500 buth support 1 Mhz and 20 Mhz. Buy upping the clocc we will get the maximum clock rate the driver
   supports that is <= 20 Mhz. This will boost the FMUv4Pro SPI speed to 11.25 Mhz (it was half that)

   The Pixkhawk mini was not chip selecting the ICM20608 as it did
   not define PX4_SPIDEV_ICM_20608. This allow the fmu V2 rc code
   to init the ICM20608.

  Insure a 0.0 voltage initial condition on VDD_3V3_SENSORS
  By starting the GPIO_VDD_3V3_SENSORS_EN, low and deferring
  the GPIO init of the slave selects and drdy signals until
  board_app_initialize. We get ~ 180 ms of power off time
  with 0.00 voltage applied to the sensors.

Add missing `.py` extension to Tools/px4 to fix #7525

This is important for multicopters for drift-free altitude changes and important for fixed wing to keep the current loiter center.