audio-hal: Detection of BT devices during voice call

When BT device is connected to target, platform selecting the speaker MIC 
instead of BT SCO as the input device.

No condition check for BT device connection
while source as VOICE_COMMUNICATION

Added condition check for the BT device connection
assigning in_device to BT

Change-Id: If1803737487c41a09593304a98c4822773f43d87