[media] DiB7000M: add pid filtering

This patch adds the pid filtering for the dib7000M demod. It also
corrects the pid filtering for the dib7700 based board. It should
prevent an oops, when using dib7700p based board.

References: https://bugzilla.novell.com/show_bug.cgi?id=644807

Signed-off-by: Olivier Grenie <olivier.grenie@dibcom.fr>
Signed-off-by: Patrick Boettcher <patrick.boettcher@dibcom.fr>
Tested-by: Pavel SKARKA <paul.sp@seznam.cz>
Cc: stable@kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>