common chconf.h: allow custom idle hooks

Author: dexter93

platforms/chibios/boards/common/configs/chconf.h

@@ -749,20 +749,22 @@
  *          should be invoked from here.
  * @note    This macro can be used to activate a power saving mode.
  */
+#if !defined(CH_CFG_IDLE_ENTER_HOOK)
 #define CH_CFG_IDLE_ENTER_HOOK() {                                          \
   /* Idle-enter code here.*/                                                \
 }
-
+#endif
 /**
  * @brief   Idle thread leave hook.
  * @note    This hook is invoked within a critical zone, no OS functions
  *          should be invoked from here.
  * @note    This macro can be used to deactivate a power saving mode.
  */
+#if !defined(CH_CFG_IDLE_LEAVE_HOOK)
 #define CH_CFG_IDLE_LEAVE_HOOK() {                                          \
   /* Idle-leave code here.*/                                                \
 }
-
+#endif
 /**
  * @brief   Idle Loop hook.
  * @details This hook is continuously invoked by the idle thread loop.