Not all 0-15 LEDs are available for all models, sometimes it's even not
safe. This patch return -NODEV while operating uninitialized LEDs.
Signed-off-by: NAdam Lee <adam.lee@canonical.com>
Acked-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: NMatthew Garrett <matthew.garrett@nebula.com>