Audio: Avoid sudden volume hike observed during SHO.

Volume hike is observed during soft hand off.

Stale data in adm is playing on the bt device selected
after SHO.

To avoid this during a2dp reconfigure before select devices
we will mute the stream and select speaker and unmute the stream
after select devices is done.So the stale data will play as mute
on speaker and no pop would be heard.

Change-Id: If9124dd1bf2255dd1cec2b0bcdff324a8945c89c