asus-laptop: let WLED alone on L1400B

Asus took the DSDT from another model (L84F), made some change
to make it work, but forgot to remove WLED method (the laptop
doesn't have a wireless card). They even didn't change the model
name.

ref: https://bugzilla.kernel.org/show_bug.cgi?id=25712



Signed-off-by: Corentin Chary <corentin.chary@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>