V4L/DVB (10371): gspca - spca561: Fix image problem in the 352x288 mode of rev72a.

With the wrong clock value, the image had two moving colored lines.

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