media: staging: tegra-vde: Support V4L stateless video decoder API

Expose Tegra video decoder as a generic V4L M2M stateless video decoder.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>