msm7x27a-common: build memtrack hal

Change-Id: I38f5b60e4c68b508f9a33c7275e5a6b972763e83
msm7x27a-common:libaudio: remove snd devices hal, we don't use it

Change-Id: I462989ee0f9f51a4d0621a9bffc5aba9bf26e177