alsa_sound: Fix for voice volume restore after reboot

  - Maximum volume is heard for call after reboot even if it
    was set to minimum during the last call before reboot.

  - During call after reboot, mLastvoiceVolume is getting
    updated improperly and hence proper volume is not
    being applied.

  - Fix is to cache the voice Volume properly.

  CRs-Fixed: 517731

Change-Id: Ia9512afaab94407f04011541db1b49b41cd5707a
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: I4d082b875a299e47407fb5b2d0b7ac54eef5adfa
Merge "  alsa_sound: Fix for voice volume restore after reboot" into cm-10.2