V4L/DVB: Report supported QAM modes on bt8xx

V4L/DVB: Report supported QAM modes on bt8xx

Here a small patch to get a TwinHan VT DST DVB-T card working with
kernels >= 2.6.32. Analogously to
http://linuxtv.org/hg/v4l-dvb/rev/0e735b509163 I had to:

"Fill in the .caps field in struct dst_dvbt_ops (around line 1763) with
all the supported QAM modulation methods to match the capabilities of
the card as implemented in function dst_set_modulation (around line
502). Note that beginning with linux kernel version 2.6.32 the
modulation method is checked (by function dvb_frontend_check_parameters
in file drivers/media/dvb/dvb-core/dvb_frontend.c) and thus tuning fails
if you use a modulation method that is not present in the .caps field."

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