audio_hal : examine SCO device in the stream list before routing to SCO

when BT_SCO=ON arrive we are routing all usecase to SCO device
but sometime SCO device not updated to stream list,so again
device switched to previous device. To avoid that we check
SCO device availability in the stream list then routing to SCO.

Change-Id: I599e07b56527f0e087bb59254b16fcc9ca278520
1 file changed