V4L/DVB: gspca_xirlink_cit: Add support for Model 1, 2 & 4 cameras

Note this is untested as I don't have hardware to test, but all
initsequences were taken over 1 on 1 from the old ibmcam driver so things
should work.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>