staging/lirc_parallel: fix panic on rmmod

lirc_parallel seems to leave a bunch of stuff around after rmmod.
Without the patch below modprobe ; rmmod ; modprobe will cause a panic.

There are still some remaining problems, (double registration of sysfs files)
but this patch is at least a start to survive the panic.

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>