wifi(implementation): Print out the cb object on failure

This should help us figure out if there are multiple callback objects in
wifi_chip when we see the IPC storm from
onDebugRingBufferDataAvailable().

Bug: 36599054
Test:  ACTS wifi tests.
Change-Id: I8c67032c59ecdd45824e131b59d890ce6c94fe25

wifi/1.0/default/wifi_chip.cpp

@@ -855,7 +855,8 @@ WifiStatus WifiChip::registerDebugRingBufferCallback() {
     for (const auto& callback : shared_ptr_this->getEventCallbacks()) {
       if (!callback->onDebugRingBufferDataAvailable(hidl_status, data).isOk()) {
         LOG(ERROR) << "Failed to invoke onDebugRingBufferDataAvailable"
-                   << " callback";
+                   << " callback on: " << toString(callback);
+
       }
     }
   };