msm8974: use 48KHz sampling rate for A2DP

This is to match

http://review.cyanogenmod.org/#/c/80463/

Change-Id: Ie706b5a252131bbc5fd6279d64f0bebbec3c6fb2
msm8974: sepolicy for display tuning knobs

Change-Id: I1cbf3a8e9aeef65a7302d9acaabcb82f06a9aaa9