The only "work-around" that I can think of is using the LastPass extension on Opera desktop instead of the native password manager. Then you can also use the LastPass app on your Android device to sync your passwords with your desktop computer(s).
This is not a perfect solution and I'd much rather have native support for password syncing between the desktop and Android browsers like you have on both Chrome and Firefox. In fact, the lack of this feature is the main reason why I've NEVER settled with Opera as my main browser. I've always used Chrome or Firefox instead of Opera because of this