HAL_ChibiOS: modify hal can drivers for use by AP_Periph

libraries/AP_HAL_ChibiOS/EventSource.cpp

@@ -1,5 +1,6 @@
 #include "EventSource.h"
-#include <AP_HAL/AP_HAL.h>
+
+#if !defined(HAL_BUILD_AP_PERIPH) && !defined(HAL_BOOTLOADER_BUILD)
 
 using namespace ChibiOS;
 
@@ -31,4 +32,5 @@ void EventSource::signalI(uint32_t evt_mask)
     ch_evt_src_.broadcastFlagsI(evt_mask);
     chSysUnlockFromISR();
 }
-#endif
+#endif //#if CH_CFG_USE_EVENTS == TRUE
+#endif //#if !defined(HAL_BUILD_AP_PERIPH) && !defined(HAL_BOOTLOADER_BUILD)