HID: apple: Add support for the 2013 Macbook Air

HID: apple: Add support for the 2013 Macbook Air

commit 9d9a04ee758b4c1fcc7586d065cdde7a7607e156 upstream.

This patch adds keyboard support for MacbookAir6,2 as WELLSPRING8
(0x0291, 0x0292, 0x0293). The touchpad is handled in a separate
bcm5974 patch, as usual.

Reported-and-tested-by: Brad Ford <plymouthffl@gmail.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>