Sound Control: Added headphone poweramp controls

Change-Id: I9e06faef4d1f0a0a5e88aa0c91cd380d48dd3d7b
sound control 3.x: Initial GPL release for WCD9310 Audio Codec

Change-Id: I1b04ac0b5ba02b4d247b17197d199102f0f40480
sound/soc/codecs/wcd9310.c: expose additional controls

Change-Id: I9569137877e47740aba08a3319cfe605e84daa04
Sound Control: (Optional) work around for WCD93xx audio issues

Change-Id: I3b218da74583ce733b619fa40d7871f3ffcad85a
Sound Control: (OPTIONAL) add power amp registers access control as well

Change-Id: I1cb557784360a59e5f33fbb4c2535d45b8cb085c
sound control: add register cache

Change-Id: Ia9627dfc4abcc565d410284102baaeeb09e7706f