AP_RCMapper: exclude body of AP_RCMapper based on AP_RCMAPPER_ENABLED

libraries/AP_RCMapper/AP_RCMapper.cpp

@@ -1,3 +1,7 @@
+#include "AP_RCMapper_config.h"
+
+#if AP_RCMAPPER_ENABLED
+
 #include <AP_HAL/AP_HAL.h>
 #include "AP_RCMapper.h"
 
@@ -75,3 +79,5 @@ RCMapper::RCMapper(void)
 RCMapper *AP::rcmap() {
     return RCMapper::get_singleton();
 }
+
+#endif  // AP_RCMAPPER_ENABLED

libraries/AP_RCMapper/AP_RCMapper_config.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <AP_HAL/AP_HAL_Boards.h>
+
 #ifndef AP_RCMAPPER_ENABLED
 #define AP_RCMAPPER_ENABLED 1
 #endif