[media] sh-vou: support compulsory G/S/ENUM_OUTPUT ioctls

Video output drivers must support these ioctls. Otherwise applications
cannot deduce that these outputs exist and what capabilities they have.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>