arch/x86: Drop CBMEM_TOP_BACKUP

Code has evolved such that there seems to be little
use for global definition of cbmem_top_chipset().
Even for AMD we had three different implementations.

Change-Id: I44805aa49eab526b940e57bd51cd1d9ae0377b4b
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43326
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/northbridge/amd/agesa/family14/state_machine.c b/src/northbridge/amd/agesa/family14/state_machine.c
index 202cdaa..36e5fd9 100644
--- a/src/northbridge/amd/agesa/family14/state_machine.c
+++ b/src/northbridge/amd/agesa/family14/state_machine.c
@@ -2,8 +2,8 @@
 
 #include <Porting.h>
 #include <AGESA.h>
+#include <amdblocks/biosram.h>
 #include <arch/io.h>
-#include <cbmem.h>
 #include <cf9_reset.h>
 #include <console/console.h>
 #include <device/device.h>