[media] dvb: don't pass a DVBv3 parameter for search() fops

Just like the other DVB algorithms, drivers should use the DVBv5
way to retrieve parameters: via the cache struct.

Actually, several drivers were partially using the DVBv3 struct
and partially using the DVBv5 way, with is confusing and may
lead into troubles.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>