media: venus: helpers: add a helper function to set dynamic buffer mode

Adds a new helper function to set dynamic buffer mode if it is
supported by current HFI version. The dynamic buffer mode is
set unconditionally for both decoder outputs.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Reviewed-by: Alexandre Courbot <acourbot@chromium.org>
Tested-by: Alexandre Courbot <acourbot@chromium.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>