mb/apple/macbookair4_2: Drop obsolete spd.bin file

After commit 940fe080bf1e (mb/apple/macbookair4_2: Correctly implement
SPD mapping the Haswell way), this file is obsolete
and can be removed.

Change-Id: I5afe6809c7097ab8529a3c1ec7befbd0d6f01c5f
Signed-off-by: Keith Hui <buurin@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78784
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin L Roth <gaumless@gmail.com>
diff --git a/src/mainboard/apple/macbookair4_2/spd.bin b/src/mainboard/apple/macbookair4_2/spd.bin
deleted file mode 100644
index 6e2738f..0000000
--- a/src/mainboard/apple/macbookair4_2/spd.bin
+++ /dev/null
Binary files differ