media: staging: tegra-vde: Reorder misc device registration

Register misc device in the end of driver's probing since device should
become visible to userspace once driver is fully prepared. Do the opposite
in case of driver removal. This is a minor improvement that doesn't solve
any problem, but makes code more consistent.

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