Makefile: Add src/soc/* to subdirs

This change adds src/soc/* to subdirs before src/soc/*/* to allow
Makefile in src/soc/* to provide any common helpers that will be
useful for any src/soc/*/*. This is done to primarily ensure that the
helpers are defined before being invoked by the SoC Makefile.inc. This
is utilized by Intel CSE stitching mechanism in following changes.

BUG=b:189177580

Change-Id: I91579a87016fdc2b9ca2d798b81969c21c18b4a3
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58124
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

Makefile.inc

@@ -81,7 +81,7 @@ PHONY+= clean-abuild coreboot check-style build_complete
 # root source directories of coreboot
 subdirs-y := src/lib src/commonlib/ src/console src/device src/acpi src/superio/common
 subdirs-y += src/ec/acpi $(wildcard src/ec/*/*) $(wildcard src/southbridge/*/*)
-subdirs-y += $(wildcard src/soc/*/*) $(wildcard src/northbridge/*/*)
+subdirs-y += $(wildcard src/soc/*) $(wildcard src/soc/*/*) $(wildcard src/northbridge/*/*)
 subdirs-y += $(wildcard src/superio/*) $(wildcard src/superio/*/*)
 subdirs-y += $(wildcard src/drivers/*) $(wildcard src/drivers/*/*) $(wildcard src/drivers/*/*/*)
 subdirs-y += src/cpu src/vendorcode