This is necessary to be able to use DMA on the IO link. We free one channel by disabling DMA entirely on the debug console.

No need for this since beat's changes in syslink_main.cpp work for connecting crazyflie to QGC. 
Will open a separate PR for it.

Discussed in https://github.com/PX4/Firmware/issues/8924

https://github.com/PX4-NuttX/nuttx/commit/efc3d9e92bd10623ab3025f012fd7d481e1a7267

In the stm32f7 the configuration variable for SD card with DMA changed from CONFIG_STM32_SDIO_DMA to CONFIG_STM32F7_SDMMC_DMA
the maximum clock speed of 16MHz can now be achieved.

 - move to ModuleBase
 - strip down to PWM 8 and 16 modes only
 - remove all dead code
 - implement missing pwm ioctls (current value, rates, etc)
 - default rate 50Hz -> 400Hz

Signed-off-by: Roman <bapstroman@gmail.com>

- fixes #8858

* Cygwin: repaired NuttX build after 1f63d858
all the NuttX specific WINTOOL define handling was skiped in cmake Make.defs generation
The Nuttx build is makfile based and needs its cygwin treatment

Additionally the ${PX4_SOURCE_DIR}/src/include which was added through cmake needs path conversion

The two root causes for the special handling are:
- ARM GCC for Windows doesn't support cygwin paths passed as an argument
  so they need to be either relative or converted via cypath tool
- Symbolic links are totally different under Windows and because NuttX uses them extensively
  it has special handling scripts that need to be fed with the correct defines

* Cygwin: NuttX include paths all converted in Make.defs.in

differentiate between WINTOOL define (MSYS & cygwin) and cygwin using uname command:
- MSYS needs symbolic link handling for ARM GCC but no path conversion
- Cygwin needs both

This is a temporary workaround for equal expressions in chip/sam_xdmac.c
and can be reverted once fixed properly in NuttX. Needed for the GCC 7
upgrade in #8551.

because the relative path is interpreted differently on linux, mac and windows

Most of the incompatitbilities are luckily similar to the darwin build.
- New target OS __PX4_CYGWIN added because in other build environments on Windows defines will very likely be completely different
- added all necessary exeptions to the defines
- disabled priorities completely because on Windows they are defined 1-32 and with all the arbitrary +40 -40 priority settings there were a lot of problems
  not only did some threads/"virtual tasks" not start because of out of bound priorities but also the resulting scheduling was totally random and inadequate
  with default priorities it ran toally fine during my first tests, should be rethought when windows is used onboard in the future

https://github.com/PX4-NuttX/nuttx/pull/7

 - this works around cygwin path issues on windows

There was and extra "nuttx" dir:
	cp: cannot stat '/home/lucas/p/dronecode/PX4/Firmware/build/aerofc-v1_default/NuttX/nuttx/nuttx/.config': No such file or directory
	FAILED: NuttX/CMakeFiles/menuconfig

And the board fixup being executed from the wrong working directory:
	nuttx-configs/aerofc-v1/nsh/defconfig
	fatal: Path 'nuttx-configs/aerofc-v1/nsh/defconfig' does not exist in 'HEAD'

   Tied to nuttx, apps  px4_firmware_nuttx-master
     rebased on upstream nuttx master @ 3647ace55958c094cfe93f07092d308a768f5ca3
     rebased on upstream apps master @ 21c9b793e2ca6f4e86388c80d7af5c466de5e71c