V4L/DVB (8933): gspca: Disable light frquency for zc3xx cs2102 Kokom.

CS2102K stop streaming on setlightfreq (50Hz & 60Hz).
Disable it for now until a correct solution is found.

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