Remove unmaintained NuttX config

Makefile

@@ -142,9 +142,6 @@ px4fmu-v2_simple:
 px4fmu-v2_lpe:
 	$(call cmake-build,nuttx_px4fmu-v2_lpe)
 
-nuttx_sim_simple:
-	$(call cmake-build,$@)
-
 posix_sitl_default:
 	$(call cmake-build,$@)
 

cmake/configs/nuttx_sim_simple.cmake

@@ -1,21 +0,0 @@
-include(nuttx/px4_impl_nuttx)
-
-message(WARNING "this is a work in progress and doesn't build yet")
-
-set(CMAKE_TOOLCHAIN_FILE ${CMAKE_SOURCE_DIR}/cmake/toolchains/Toolchain-native.cmake)
-
-set(config_module_list
-	#platforms/nuttx
-	#platforms/nuttx/px4_layer
-	platforms/common
-	#drivers/led
-	drivers/device
-	#modules/systemlib
-	#modules/uORB
-	#examples/px4_simple_app
-	#lib/mathlib/math/filter
-	#lib/conversion
-	)
-
-set(config_extra_builtin_cmds
-	)