V4L/DVB (6211): pvrusb2: Allocate a debug mask bit for reporting video standard things

It's useful to see specific details for how the pvrusb2 driver is
figuring out things related to the video standard, independent of
other initialization activities.  So let's set up a separate debug
mask bit for this and turn it on.

Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>