Re-enable legacy driver compatibility

https://github.com/kumajaya/android_device_samsung_lt013g/commit/a576ff1070d58c53d9d8630612c579dd1f5240d0
overlay: send mic mute to audio manager
Disable button backlight for now
Merge common overlay config to common-overlay

https://github.com/kumajaya/android_device_samsung_lt013g/commit/b3755c5541db4cac13534a8e994f39559d720d9e