alsa_sound: separate fast CSD call device switching from CSD sessions

* This was two separate commits from upstream, some devices may have
  support for CSD sessions but no support for the fast call switching
  functionality.

Change-Id: I74951e3bad0c4ace1c889b3481c141f047e3ef0e
Merge pull request #1 from omnirom/android-4.4

alsa_sound: separate fast CSD call device switching from CSD sessions