st/omx: initial OpenMAX H264 encoder v7

st/omx: initial OpenMAX H264 encoder v7

v2 (chk): fix eos handling
v3 (leo): implement scaling configuration support
v4 (leo): fix bitrate bug
v5 (chk): add workaround for bug in Bellagio
v6 (chk): fix div by 0 if framerate isn't known,
          user separate pipe object for scale and transfer,
          always flush the transfer pipe before encoding
v7 (chk): make suggested changes, cleanup a bit more,
          only advertise encoder on supported hardware

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Leo Liu <leo.liu@amd.com>