hid/apple: modern macbook airs use the standard apple function key translations

This removes the use of the special "macbookair_fn_keys" keyboard
translation table for the MacBookAir4,x models (ie the 2011 refresh).
They use the standard apple_fn_keys[] translation.  Apparently only the
old MacBook Air's need a different translation table.

This mirrors the change that commit da617c7c ("HID: consolidate
MacbookAir 4,1 mappings") did for the WELLSPRING6A ones, but does it for
the WELLSPRING6 model used on the MacBookAir4,2.

Reported-and-tested-by: Dirk Hohndel <hohndel@infradead.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Joshua V Dillon <jvdillon@gmail.com>
Cc: Chase Douglas <chase.douglas@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>