V4L/DVB (7166): [v4l] Add new user class controls and deprecate others

These changes should appear in the next update of the v4l2spec.

HCENTER and VCENTER are unused in the tree so I added a _DEPRECATED
postfix so applications can remove their use.

Signed-off-by: Brandon Philips <bphilips@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>