* some fixes around the powerOff(). Tidy ups

src/MeshCore.h

@@ -40,7 +40,7 @@ public:
   virtual void onBeforeTransmit() { }
   virtual void onAfterTransmit() { }
   virtual void reboot() = 0;
-  virtual void powerOff() { while (1) { }}; // hope it's overriden or never called ;)
+  virtual void powerOff() { /* no op */ }
   virtual uint8_t getStartupReason() const = 0;
   virtual bool startOTAUpdate() { return false; }   // not supported
 };

src/helpers/HeltecV3Board.h

@@ -68,7 +68,8 @@ public:
   }
 
   void powerOff() override {
-    enterDeepSleep(0);
+    // TODO: re-enable this when there is a definite wake-up source pin:
+    //  enterDeepSleep(0);
   }
 
   uint16_t getBattMilliVolts() override {