[media] marvell-ccic: webcam drivers shouldn't support g/s_std

TV standards make no sense for webcam drivers, so drop these dummy
functions. This stops v4l2-compliance from complaining about this.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>