media: venus: venc: fix bytesused v4l2_plane field

This fixes wrongly filled bytesused field of v4l2_plane structure
by include data_offset in the plane, Also fill data_offset and
bytesused for capture type of buffers only.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: <stable@vger.kernel.org>      # for v4.13 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>