util/amdfwtool: add missing zero-initialization for local variable

Change-Id: Ib156b16b874f74f58bd816071db3a7acf33c5aaf
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47817
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/util/amdfwtool/data_parse.c b/util/amdfwtool/data_parse.c
index c2ce32b..21e7317 100644
--- a/util/amdfwtool/data_parse.c
+++ b/util/amdfwtool/data_parse.c
@@ -224,7 +224,8 @@
 {
 	amd_bios_type fw_type = AMD_BIOS_INVALID;
 	amd_bios_entry *bhd_tableptr;
-	uint8_t subprog, instance = 0;
+	uint8_t subprog = 0;
+	uint8_t instance = 0;
 
 	(void) (cb_config);	/* Remove warning and reserved for future. */