Fixes an oops when an lirc driver that doesn't provide its own fops is
unplugged while the lirc cdev is open. Tested with lirc_igorplugusb,
with a special thanks to Timo Boettcher for providing the test hardware.
Signed-off-by: NJarod Wilson <jarod@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>