hal: remove output device force switch from bt sco to handset

Trailing sound may leak to handset after doing force switch
from bt sco output device.
Since when a2dp device is selected, all active output streams
will also route to a2dp during check_usecases_codec_backend,
then a2dp and bt sco won't be active concurrently. But sco
input device can be concurrent with a2dp device, so only
check force switch of input device when SCO is off.

Change-Id: I8225859dc9a3da987ace6cee3225c375785d3bea