kbuild: automatically include SOCs

This change switches all SOC vendors and southbridges
to be autoincluded by Makefile.inc, rather than having to be
mentioned explicitly in soc/Makefile.inc or in
soc/<vendor>/Makefile.inc.

This means, vendor and SOC directories are now "drop
in", e.g. be placed in the coreboot directory hierarchy
without having to modify any higher level coreboot files.

The long term plan is to enable out of tree components to be
built with a given coreboot version (given that the API did not
change).

Change-Id: Iede26fe184b09c53cec23a545d04953701cbc41d
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: http://review.coreboot.org/9799
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

Makefile.inc

@@ -54,7 +54,7 @@ PHONY+= clean-abuild coreboot lint lint-stable build-dirs
 # root source directories of coreboot
 subdirs-y := src/lib src/console src/device
 subdirs-y += src/ec/acpi $(wildcard src/ec/*/*) $(wildcard src/southbridge/*/*)
-subdirs-y += src/soc
+subdirs-y += $(wildcard src/soc/*/*)
 subdirs-y += src/northbridge src/superio src/drivers src/cpu src/vendorcode
 subdirs-y += util/cbfstool util/sconfig util/nvramtool util/broadcom
 subdirs-y += $(wildcard src/arch/*)