[media] staging: lirc: use octal instead of symbolic permission

Changed permissions to octal across whole driver
Found by checkpatch

Signed-off-by: Derek Robson <robsonde@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>