soc/amd/common/block/acpi/bert: fix NULL check

In acpi_soc_get_bert_region after the bert_errors_region call is was
checked if the region parameter is NULL after the call; since region is
a parameter of acpi_soc_get_bert_region, it's non-NULL. What we should
be checking here is if region points to a non-NULL pointer.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Reported-by: Coverity (CID:1457506)
Change-Id: I0523504d65725ab2d2df4db28a5dedd90697b917
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55541
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/soc/amd/common/block/acpi/bert.c

@@ -16,7 +16,7 @@ enum cb_err acpi_soc_get_bert_region(void **region, size_t *length)
 		return CB_ERR;
 
 	bert_errors_region(region, length);
-	if (!region) {
+	if (!*region) {
 		printk(BIOS_ERR, "Error: Can't find BERT storage area\n");
 		return CB_ERR;
 	}