vendorcode/amd/pi/00670f00: Set ModuleIdentifier to be 8 bytes

ModuleIdentifier must be 8 bytes.   Every other location else that uses
this value explicityly defines it as 8 bytes.  If it's initialized here
to less than 8 bytes, it gets passed to those other locations with
garbage at the end and fails to load the AGESA binary.

TEST=Build & boot Kahlee
BUG=B:69165234

Change-Id: I11fc90748f49782e2b16ee5326aee17cfe92d0bc
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/22430
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Justin TerAvest <teravest@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/vendorcode/amd/pi/00670F00/binaryPI/AGESA.c

@@ -53,7 +53,7 @@
 
 CONST UINT32 ImageSignature = IMAGE_SIGNATURE;
 CONST UINT32 ModuleSignature = MODULE_SIGNATURE;
-CONST CHAR8 ModuleIdentifier[] = AGESA_ID;
+CONST CHAR8 ModuleIdentifier[8] = AGESA_ID;
 
 /**********************************************************************
  * Interface call:  AmdCreateStruct