Update submodule nuttx to latest Sat Feb 8 00:39:27 UTC 2020

[dagar]

- nuttx in PX4/Firmware (ea41c2c95aaab87942c25f6b8e626839f3c66a49): https://github.com/PX4/NuttX/commit/7b36108b548642f1a8513dcf00eb4913f8558ccf
- nuttx current upstream: https://github.com/PX4/NuttX/commit/fdf1837077104e80912a2c46ff159fdacc8b06f9
- Changes: https://github.com/PX4/NuttX/compare/7b36108b548642f1a8513dcf00eb4913f8558ccf...fdf1837077104e80912a2c46ff159fdacc8b06f9

fdf1837077 2020-02-07 Peter van der Perk - [BACKPORT] S32K add support for Nxp drone boards (#224)

f479b26c98 2020-02-07 Peter van der Perk - [BACKPORT] imxrt added missing i2c prescale mask
26dd187034 2020-02-07 Peter van der Perk - [BACKPORT] Kinetis renamed TJA1100 to TJA110X registers

[codecov]

Codecov Report

Merging #14117 into master will decrease coverage by 1.12%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #14117      +/-   ##
==========================================
- Coverage   37.36%   36.24%   -1.13%     
==========================================
  Files         570      552      -18     
  Lines       47670    47123     -547     
==========================================
- Hits        17814    17078     -736     
- Misses      29856    30045     +189

Flag	Coverage Δ
#mavsdk	36.24% <ø> (+0.04%)	⬆️
#sitl_mission_MC_box	?
#sitl_mission_MC_offboard_pos	?
#sitl_mission_Rover	?
#sitl_mission_VTOL_standard	?
#sitl_mission_VTOL_tailsitter	?
#sitl_python_FW	?
#sitl_python_MC_box	?
#sitl_python_MC_offboard_pos	?
#sitl_python_Rover	?
#sitl_python_VTOL_standard	?
#sitl_python_VTOL_tailsitter	?

Impacted Files	Coverage Δ
...modules/rover_pos_control/RoverPositionControl.hpp	0% <0%> (-100%)	⬇️
src/modules/land_detector/RoverLandDetector.cpp	0% <0%> (-100%)	⬇️
src/lib/mixer/NullMixer/NullMixer.cpp	0% <0%> (-84.62%)	⬇️
src/lib/pid/pid.cpp	0% <0%> (-72.59%)	⬇️
platforms/posix/src/px4/common/lib_crc32.c	0% <0%> (-66.67%)	⬇️
src/lib/weather_vane/WeatherVane.cpp	30% <0%> (-65%)	⬇️
...modules/rover_pos_control/RoverPositionControl.cpp	0% <0%> (-63.87%)	⬇️
src/modules/land_detector/RoverLandDetector.h	0% <0%> (-50%)	⬇️
src/modules/land_detector/LandDetector.h	22.22% <0%> (-44.45%)	⬇️
src/modules/navigator/mission.h	20% <0%> (-30%)	⬇️
... and 53 more