media: Revert "media: dt-bindings: Document the Rockchip VPU bindings"

This reverts commit e4183d32

.

The commit was picked by mistake, as the Rockchip VPU driver
is not ready for inclusion yet, and it's still under discussion.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>