acpi: Fix Coverity Scan report

Fix the issue that return value "r" in line 534 will get overwritten
problem.

BUG=CID 1445995
TEST=Build sucessful and boot up in QEMU

Signed-off-by: Lijian Zhao <lijian.zhao@intel.com>
Change-Id: Icf760b142cfecfed7c929c15ad190ac74df027b1
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50352
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Francois Toguo Fotso <francois.toguo.fotso@intel.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
diff --git a/src/arch/x86/acpi_bert_storage.c b/src/arch/x86/acpi_bert_storage.c
index f1dcf47..b07b67e 100644
--- a/src/arch/x86/acpi_bert_storage.c
+++ b/src/arch/x86/acpi_bert_storage.c
@@ -534,7 +534,7 @@
 		r = bert_append_genproc(status);
 	else if (!guidcmp(guid, &CPER_SEC_PROC_GENERIC_GUID))
 		r = bert_append_ia32x64(status);
-	if (!guidcmp(guid, &CPER_SEC_FW_ERR_REC_REF_GUID))
+	else if (!guidcmp(guid, &CPER_SEC_FW_ERR_REC_REF_GUID))
 		r = bert_append_fw_err(status);
 	/* else if other types not implemented */
 	else