hlte: Audio update

 * Recreate mixer_paths.xml from Samsung's 4.4 release
 * Don't hack up all the path names, just use the platform API to
   override what the HAL expects normally.
 * Added extra paths such as USB audio, HFP, Listen, proxy, etc.
 * Add USB digital support for VOIP calls (need to merge AV path still)

Change-Id: I292a42fd99d61fa112e072c063f70f080f032d1b
hlte: Enable hardware keystore

 * Also a few SELinux related fixes.

Change-Id: Ibebbbdbf62d997d7d23c16e64eee3f645cf93c1b