Makefile.mk: Put site-local path first

"site-local" Makfile(s) may need to override some of the macros/paths
used elsewhere in src/* Makefiles. If we include it last src/*
Makefile.mk will have already been processed. MAINBOARD_BLOBS_DIR is
an example where the path needs to be overwritten in site-local
requiring it to be included first before src/mainboard/* Makefile.mk
is processed.

Change-Id: I8ea865cd73aba5092a628b0422e5c4121b32fb4d
Signed-off-by: Nikolai Vyssotski <nikolai.vyssotski@amd.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/68799
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/Makefile.mk b/Makefile.mk
index 3cfd97c..301a3bc 100644
--- a/Makefile.mk
+++ b/Makefile.mk
@@ -96,6 +96,9 @@
 
 #######################################################################
 # root source directories of coreboot
+# site-local Makefile.mk must go first to override default locations (for binaries etc.)
+subdirs-y := site-local
+
 subdirs-y := src/lib src/commonlib/ src/console src/device src/acpi src/superio/common
 subdirs-$(CONFIG_EC_ACPI) += src/ec/intel
 subdirs-y += src/ec/acpi $(wildcard src/ec/*/*) $(wildcard src/southbridge/*/*)
@@ -112,8 +115,6 @@
 subdirs-y += src/security
 subdirs-y += payloads payloads/external
 subdirs-$(CONFIG_SBOM) += src/sbom
-
-subdirs-y += site-local
 subdirs-y += util/checklist util/testing
 
 #######################################################################