media: staging: tegra-vde: Remove legacy UAPI support

The legacy UAPI became unnecessary with the V4L stateless decoder API
support addition to the Tegra decoder driver. Remove legacy UAPI support.

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>