Audio: Restore volume for all streams on headset connect/disconnect

Audio streams which play sound from both speaker and a connected device would
report to AudioService only the speaker as the playback device, meaning volumes
would not be saved for a separate device state. This patch makes it so the
connected device will be reported instead, fixing volume restore on device
change for those streams (alarm, ring, notifications).

Readded safe headset restore capping for all streams.

Patch Set 3: Changed cap to 10/15

Change-Id: Ie78bde2f661e7d9f2e81373390a4a77d3dd4525b
Restore correct volumes when headset is plugged
The correct volume levels for <device>_speaker and
<device>_headset are not restored when a headset device
is plugged in or out

Change-Id: Ib8d3fa4c9c3fac7f9a5878fcb43978391af74539