soc/amd/*: Enable override of MAINBOARD_BLOBS_DIR

MAINBOARD_BLOBS_DIR is defined the same way by
picasso/cezanne/mendocino/phoenix/glinda and unused by stoneyridge, so
move it to a common area.

This makefile variable is currently only used to locate APCB blobs for
the different mainboards.

Add a Kconfig option to point to the APCB blobs directory. This allows
simple overriding to locations such as site-local.

TEST=Timeless builds

Signed-off-by: Fred Reitberger <reitbergerfred@gmail.com>
Change-Id: I0702fdb97fbc2c73d97994ab4d5161ff0f467518
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69410
Reviewed-by: Jason Glenesk <jason.glenesk@amd.corp-partner.google.com>
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions