Revert "audio: Fix incall device switch handling"

This commit cause bug - no sound after end voice call when
using speaker. Sound come back after audioflinger send
standby and hal reenable speaker for new stream (usecase).

Reason - hal need reenable speaker (or other devices) for
other streams (usecases).

This reverts commit f33a728b205f7656ca6211a07e3dd69c623b75ca.

Change-Id: Icde4e83ab824008e931b681cdbb6e11d6a2a7aa5