Update the sniff policy when SCO is active

Use case:
1. Connect BT headset.
2. Make an outgoing call or receive a call on BT headset.
3. Check if sniff parameters are taking affect when SCO is active.

Failure:
Sniff parameters when SCO is active are not taking affect.

Root cause:
SCO link was not checked when updating power manager(PM)
about idle or busy states.

Fix:
During AG tx/rx activity, update PM based on SCO state.

Change-Id: I4c09406395998bacf13471a273402a60f3b77f89