hal: fix voip device selection is not proper after voice call stop

In voip+voice concurrency case, when voip resume after voice call stop,
voip device still uses voice devices. This is due to in_call flag isn't
reset even if voice usecase doesn't exist.

Fix it by adding function to check voice usecase existence and get
correct device for non-voice usecases.

Change-Id: I39ba1092a0ab19c686baa1b80bb9913f64849590