util/apcb: Add apcb edit tool for phoenix

Add a new apcb edit tool, apcb_v3a_edit.py, that injects SPDs into
an APCB for phoenix platform.

The tool makes several assumptions:
 * Each SPD only uses blocks 0, 1, 3 and 5. All other blocks are zero.
 * Each block is 64 bytes.
 * Dimm and socket are always 0
 * Unused SPD entries are zero'd

BUG=b:281983434
BRANCH=None
TEST=build, flash, boot myst

Change-Id: Ifb50287de77138170714a702ab87d56427aacfef
Signed-off-by: Rob Barnes <robbarnes@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76188
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/Makefile.inc b/Makefile.inc
index 9a34c61..0d38ea3 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -615,6 +615,8 @@
 
 APCB_V3_EDIT_TOOL:=$(top)/util/apcb/apcb_v3_edit.py
 
+APCB_V3A_EDIT_TOOL:=$(top)/util/apcb/apcb_v3a_edit.py
+
 CBOOTIMAGE:=$(objutil)/cbootimage/cbootimage
 
 FUTILITY?=$(objutil)/futility/futility