Sound Control: (Optional) work around for Nexus 4/5 audio issues

(Use this only for devices with audio reset issues)

Also bump version to 3.1

Signed-off-by: Paul Reioux <reioux@gmail.com>

wcd9xxx-core: add register write without mutex protection

This is assuming the calling function will take care of the mutex.

Change-Id: I3e9eff292c3af23a60bb1473c18411c8fba62a94
Signed-off-by: Paul Reioux <reioux@gmail.com>
Sound Control: (OPTIONAL) add power amp registers access control as well

Change-Id: I1c622dc81d81fd64c44d50677dcd6cb5df7c7639
Signed-off-by: Paul Reioux <reioux@gmail.com>