Remove size optimization for individual modules

It makes more sense to set the optimization flags on a platform basis
instead of individually for each module. This allows for different
optimization options for SITL, NuttX, Snapdragon, etc.

src/modules/uavcan/CMakeLists.txt

@@ -59,7 +59,6 @@ px4_add_module(
 	STACK_MAIN 3200
 	STACK_MAX 1500
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		# Main
 		uavcan_main.cpp
@@ -81,4 +80,4 @@ px4_add_module(
 		uavcan
 	)
 
-## vim: set noet ft=cmake fenc=utf-8 ff=unix : 
+## vim: set noet ft=cmake fenc=utf-8 ff=unix :