V4L/DVB (12282): gspca - main: Support for vidioc_g_chip_ident and vidioc_g/s_register.

Signed-off-by: Brian Johnson <brijohn@gmail.com>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>