media: venus: dynamic handling of bitrate

Any request for a change in bitrate after both planes
are streamed on is handled by setting the target bitrate
property to hardware.

Signed-off-by: Malathi Gottam <mgottam@codeaurora.org>
Acked-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>