power: supply: max17040: synchronize work cancellation on suspend

In the Linux kernel, the following vulnerability has been resolved: power: supply: max17040: synchronize work cancellation on suspend max17040_work() requeues itself after every poll. cancel_delayed_work() only cancels a pending instance and does not wait for a callback that is already running. If system suspend races with the polling callback, the callback can continue accessing the fuel gauge and requeue itself after the suspend callback returns. Use cancel_delayed_work_sync() to ensure polling is quiesced before suspend completes.