libstagefright: Enable LPA playback on BT-A2DP devices.

-Applicable for msm8660, msm7630 & msm7627a.
-LPAPlayer need to be put in a new file for the above
 targets as proxy port kind of implemention that is used
 for LPA on BT in 8960 is not available for the above targets.
-Consider LPA & Tunnel player compilation only for  QCOM
 targets as it was in ICS.

Change-Id: I638bd8427a7420e7e27b711008e9c6a51fb761b5