V4L/DVB (5611): M920x: replace deb_rc with deb

deb_rc is used by the dvb-usb core framework.  This patch replaces all
occurances of deb_rc with deb, in m920x.c, so that its clear that we're
not using dvb-usb's deb_rc.

Signed-off-by: Aapo Tahkola <aet@rasterburn.org>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>