soc/amd/cezanne,common,picasso: use BERT region reserved by FSP driver

commit ce0e2a014009390c4527e064efb59260ef4d3a3b (drivers/intel/fsp2_0:
use FSP to allocate APEI BERT memory region) adds a mechanism to reserve
the BERT region inside the coreboot code, so we can get rid of the
workaround to reserve it in the FSP and return the location in a HOB.
mcfg->bert_size defaults to 0 which makes the FSP not generate the
corresponding HOB, but that field is planned to be removed at least on
Cezanne, so don't explicitly set it to 0.

BUG=b:169934025
TEST=BERT table that gets generated in a follow-up patch for Picasso
points to expected BERT region and Linux is able to access, decode and
display it.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Iaca89b47793bf9982181560f026459a18e7db134
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52584
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/common/block/cpu/noncar/memmap.c b/src/soc/amd/common/block/cpu/noncar/memmap.c
index 6ec437c..c4a9643 100644
--- a/src/soc/amd/common/block/cpu/noncar/memmap.c
+++ b/src/soc/amd/common/block/cpu/noncar/memmap.c
@@ -62,19 +62,7 @@
 
 void bert_reserved_region(void **start, size_t *size)
 {
-	struct range_entry bert;
-	int status;
-
-	*start = NULL;
-	*size = 0;
-
-	status = fsp_find_range_hob(&bert, AMD_FSP_BERT_HOB_GUID.b);
-
-	if (status < 0) {
-		printk(BIOS_ERR, "Error: unable to find BERT HOB\n");
-		return;
-	}
-
-	*start = (void *)(uintptr_t)range_entry_base(&bert);
-	*size = range_entry_size(&bert);
+	*start = cbmem_top();
+	*size = CONFIG_ACPI_BERT_SIZE;
+	printk(BIOS_INFO, "Reserved BERT region base: %p, size: 0x%lx\n", *start, *size);
 }