Autogenerate MacBookAir4,2

Just ran autoport on the data from MacBookAir4,2

Change-Id: Iba2a56a6846d81d29e6b090a9a31253ce240914d
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/11840
Tested-by: build bot (Jenkins)
Reviewed-by: Philipp Deppenwiese <zaolin@das-labor.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/src/mainboard/apple/macbookair4_2/Makefile.inc b/src/mainboard/apple/macbookair4_2/Makefile.inc
new file mode 100644
index 0000000..6064cea
--- /dev/null
+++ b/src/mainboard/apple/macbookair4_2/Makefile.inc
@@ -0,0 +1,3 @@
+romstage-y += early_southbridge.c
+romstage-y += gpio.c
+ramstage-y += gnvs.c