samsung-laptop: add true rfkill support for swsmi

The wireless status get and get commands seems to use one
byte per device. First byte is for wlan and third is for bluetooh,
we will have to find what the other are for.

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Matthew Garrett <mjg@redhat.com>