[media] coda: set umask 0644 on debug module param

Otherwise module/coda/parameters/coda_debug won't show up in sysfs.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>