Fix FM audio routing

And finally, the fight to get this working correctly and reliably has
been won.

Most importantly, this uses DEVICE_OUT_FM to signal that FM is enabled
so that volume control can work as intended.

Change-Id: Ifd96612d59b7c49167524071deea5a0291868c23
Add patch: fix SystemServer glitches due to FM merge

Change-Id: I90a6e188864fdc082e3b5eef3b88a2cb8f9e499e
Build libfmradio by default

Change-Id: I2d195105d47e3bfda7aa5a775a5f245f62265532