V4L/DVB (8724): dvb: drx397xD: checkpatch.pl cleanups

This driver sure needs some rework. For now, let's
try to clean it up a bit before start reimplementing
anything.

checkpatch.pl still not happy with this driver after
this patch, but the most annoying errors are gone,
comments now use C-style only, labels are well placed
and some other minor fixes.

Some more clean up patches will come as I work on this
driver. Please review it carefully.

Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Henk Vergonet <henk.vergonet@gmail.com>
[mchehab@infradead.org: Manually fixed some conflicts with a previous patch]
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>