[media] timblogiw: Fix sparse warning

Fixes the below warning:
drivers/media/platform/timblogiw.c:81:31: warning:
symbol 'timblogiw_tvnorms' was not declared. Should it be static?

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>