V4L/DVB (9223): MFE: Fix a number of bugs and some tidying up

A number of reference to videobuf_dvb_get_frontend used an invalid
index. This has been fixed.

The section for the HVR3000 in advise_acquire was redundant as
the same logic is used on the HVR4000. This has been removed
and both cards now use the same function.

A number of small errors and whitespace errors are also fixed.

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