media: em28xx: disable null packet filter for WinTVdualHD

This patch disables the null packet filter for the Hauppauge
WinTV-dualHD. There are applications which require the unfiltered
transport stream (e.g. DOCSIS segment load analyzers).

Tests showed that the device is capable of delivering two unfiltered
EuroDOCSIS 3.0 transport streams simultaneously, i.e. over 100 Mbit/s
worth of data, without any losses.

Signed-off-by: Robert Schlabbach <Robert.Schlabbach@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>