Changed circuit_breaker to not use px4.h

The inclusion of px4.h requires C++ features not supported in the
Hexagon toolchain. The features are not required so the required
headers are used instead.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/modules/systemlib/circuit_breaker.cpp

@@ -42,7 +42,8 @@
  * parameter needs to set to the key (magic).
  */
 
-#include <px4.h>
+#include <stdint.h>
+#include <px4_defines.h>
 #include <systemlib/circuit_breaker.h>
 
 bool circuit_breaker_enabled(const char *breaker, int32_t magic)

src/modules/systemlib/module.mk

@@ -49,17 +49,17 @@ SRCS		 = err.c \
 		   otp.c \
 		   board_serial.c \
 		   pwm_limit/pwm_limit.c \
-		   mcu_version.c
+		   mcu_version.c \
+		   bson/tinybson.c \
+		   circuit_breaker.cpp \
+		   circuit_breaker_params.c 
 
 ifeq ($(PX4_TARGET_OS),nuttx)
 SRCS		+= up_cxxinitialize.c 
 endif
 
 ifneq ($(PX4_TARGET_OS),qurt)
-SRCS 		+= hx_stream.c \
-		   circuit_breaker.cpp \
-		   circuit_breaker_params.c \
-		   bson/tinybson.c
+SRCS 		+= hx_stream.c 
 endif
 
 MAXOPTIMIZATION	 = -Os