[media] v4l2-core: remove support for obsolete VIDIOC_DBG_G_CHIP_IDENT

This has been replaced by the new and much better VIDIOC_DBG_G_CHIP_INFO.

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