mm-video: vidc:  release registered buffers from driver

In some scenarios, component may restart from loaded to idle
state in the same context and it is resulting in the preapare
buf failure as previous buffers are not unregistered. Unregister
the buffers from driver while stopping the component.

b/11051201

Signed-off: Manikanta Kanamarlapudi<kmanikan@codeaurora.org>

Change-Id: I048cf715d2e83b05df99eaf10776cff0bbb2acd2
mm-video: venc: switch between executing and loaded.

when the v4l2 modules stopped, it will free all output
and input buffers. So when it is re-started again,
re-do the VIDIOC_REQBUFS command again.

b/11051201
Signed-off: Kim Zhang<xiazhang@codeaurora.org>
Change-Id: I7c6de237fdd7476ca4ebc7d1f1016e86f3af9d95
mm-video: vidc: venc: add set ctrl to request sequence header

The omx component can explicitly request for sequence header
using the set ctrl id - V4L2_CID_MPEG_VIDC_VIDEO_REQUEST_SEQ_HEADER.
The omx component should not rely on the driver to
send sequence header on it's own.

b/11051201

Change-Id: Ie5c2adc11c15b84a7f659d75357a09b7758ea199
Merge tag 'tags/android-4.4.2_r2' into HEAD

Android 4.4.2 Release 2