media: pci: zoran: Remove unused debug parameter

Nothing has checked the zr36067_debug variable since 2021 after
commit efdd0d42 ("media: staging: media: zoran: remove
detect_guest_activity")

It's set as a module parameter, remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>