libstagefright: Add flag to use MM heap for SurfaceMediaSource

 * Older QCOM camera drivers need to use the MM heap for effects
   recording. Add a a flag to enable this.
Conflicts:
	media/libstagefright/Android.mk

Change-Id: I4a9b939081150b0b44aa5399e5fd0be18d11c642

Conflicts:
	media/libstagefright/Android.mk