V4L/DVB (11880): cx23885: support for card Mygica X8506 DMB-TH

This patch add cx23885 support for card "Mygica X8506 DMB-TH".
It should work on "Magic-Pro ProHDTV Extreme" as well, as they are
same hardware with different branding.

Sign-off-by: David T.L. Wong <davidtlwong@gmail.com>

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>