media: verisilicon: Explicitly disable selection api ioctls for decoders

media: verisilicon: Explicitly disable selection api ioctls for decoders

Call the dedicated v4l2_disable_ioctl helper instead of manually
checking whether the current context is an encoder for the selection
api ioctls.

Signed-off-by: Paul Kocialkowski <paulk@sys-base.io>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>