mb/google/zork: Fix SPD typo in trembyle makefile

Relative path to spd directory was wrong.

BUG=b:167175547
TEST=Boot Trembyle SKU 2

Change-Id: I63ae4f39ba69d2d80c25ac7383b6eb953901f56d
Signed-off-by: Rob Barnes <robbarnes@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44946
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Matt Papageorge <matthewpapa07@gmail.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/zork/variants/trembyle/Makefile.inc

@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 
-subdirs-y += ../spd
+subdirs-y += ./spd
 
 ramstage-y += gpio.c