Update src/darwin/Framework/CHIP/MTRDevice_XPC.mm

Co-authored-by: Boris Zbarsky <bzbarsky@apple.com>

src/darwin/Framework/CHIP/MTRDevice_XPC.mm

@@ -156,7 +156,7 @@ - (void)_delegateAdded:(id<MTRDeviceDelegate>)delegate
     [super _delegateAdded:delegate];
     MTR_LOG("%@ delegate added: %@", self, delegate);
 
-    // dispatch to own queue to exit lock when calling out to other code
+    // dispatch to own queue so we're not holding our lock while calling out to the controller code.
     dispatch_async(self.queue, ^{
         [(MTRDeviceController_XPC *) [self deviceController] _updateRegistrationInfo];
     });