V4L/DVB (8872): gspca: Bad image format and offset with rev072a of spca561.

- have 2 pixfmt tables
- offset of Bayer frames at 16 instead of 20.

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