V4L/DVB (12428): hdpvr: add missing initialization of current_norm

Drivers should either set current_norm or supply a g_std callback.

The hdpvr driver does neither. Since it initializes to a 60 Hz format
I've initialized the current_norm to NTSC | PAL_M | PAL_60 which is the
60 Hz subset of tvnorms.

Cc: Janne Grunau <j@jannau.net>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>