[media] drxk_hard: fix the return code from an error handler

[media] drxk_hard: fix the return code from an error handler

While it is very unlikely, if the number of parameters for
QAMDemodulatorCommand is not 2 or 4, status become undefined:

/home/hans/work/build/v4l-dvb-git/drivers/media/dvb-frontends/drxk_hard.c: In function ‘QAMDemodulatorCommand’:
/home/hans/work/build/v4l-dvb-git/drivers/media/dvb-frontends/drxk_hard.c:5452:5: warning: ‘status’ may be used uninitialized in this function [-Wuninitialized]

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