V4L/DVB (5694): M920x: fix for Dposh devices

Make sure devices manufactured by Dposh are not affected by previous hw 
pid filtering changes

Doing so might crash it.

Signed-off-by: Aapo Tahkola <aet@rasterburn.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>