V4L/DVB (8201): gspca: v4l2_pix_format in each subdriver.

main:     Parameter comp_fac removed.
main, pac207:
          get_buff_size op removed.
(all)     v4l2_pix_format in each subdriver.

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>