V4L/DVB (9224): MFE: bugfix: add missing frontend allocation

When using MFE on a setup with both and HVR-3000 and ASUS P7131
card it was noticed that frontend allocation for saa7134
adapters was missing. This patch adds that allocation for
both saa7134 and cx23885 adapters.

Signed-off-by: Darron Broad <darron@kewl.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>