cc3200: Fix bootloader build error.

cc3200/misc/mperror.c

@@ -64,7 +64,9 @@
 /******************************************************************************
  DECLARE PRIVATE DATA
  ******************************************************************************/
+#ifndef BOOTLOADER
 STATIC const mp_obj_base_t pyb_heartbeat_obj = {&pyb_heartbeat_type};
+#endif
 
 struct mperror_heart_beat {
     uint32_t off_time;