Cleanup of module building.

src/platforms/nuttx/px4_layer/px4_nuttx_tasks.c

@@ -50,7 +50,9 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
+#ifndef CONFIG_ARCH_BOARD_SIM
 #include <stm32_pwr.h>
+#endif
 
 #include <systemlib/systemlib.h>
 
@@ -61,7 +63,9 @@ void
 px4_systemreset(bool to_bootloader)
 {
 	if (to_bootloader) {
+#ifndef CONFIG_ARCH_BOARD_SIM
 		stm32_pwr_enablebkp();
+#endif
 
 		/* XXX wow, this is evil - write a magic number into backup register zero */
 		*(uint32_t *)0x40002850 = 0xb007b007;