Makefiles: Add site_local-target to run early in the build

This double-colon target doesn't do anything unless it's implemented by
another makefile. It's intended to be used only by the site-local
makefile to allow it to run any necessary steps before the actual
coreboot build begins.

Signed-off-by: Martin Roth <gaumless@gmail.com>
Change-Id: I01f98c9cf8375bca21ab87f9becf66a25402c758
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83198
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@amd.corp-partner.google.com>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

0 files changed, 0 insertions, 0 deletions