libstagefright: Allow using camera recording buffer as input for encoder

Can be enabled with global cflag SEMC_ICS_CAMERA_BLOB

Change-Id: I6dce1390bd611e9ce318d2aef0da22f843a2632b
libstagefright: Fix video encoder input buffer

Ported from cm10, needed to avoid the encoder eating up all input buffers,
which leaves no buffer left for the camera sometimes

Change-Id: I0432cd87a9defd08725ac8831d7376edb98d7e18