msm: mdss: Remove debug fs

Change-Id: I23ecc73b5d3dbe8a9b2fa1506e8b42f6a72196fa
msm: mdss: Add display gamma tuning

Change-Id: Iaa35d99409155fc7fe097d103756381391bf17e4
msm: mdss: Restore gamma interface compatibility

Make this stuff compatible with all flavors and apps.

Change-Id: I90cbc3f9ae77e590b0c9232c4c54a3970eb9861c