ich_descriptors_tool: Fix an off-by-one

BUG=chromium:478356
BRANCH=none
TEST=still builds

Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/19045
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Change-Id: Ie0d81d4b92a45d576439fc03d0efbe0d8860fb47
Signed-off-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/flashrom/+/1672911
Reviewed-by: Sam McNally <sammc@chromium.org>
diff --git a/util/ich_descriptors_tool/ich_descriptors_tool.c b/util/ich_descriptors_tool/ich_descriptors_tool.c
index 0243666..49d4a5a 100644
--- a/util/ich_descriptors_tool/ich_descriptors_tool.c
+++ b/util/ich_descriptors_tool/ich_descriptors_tool.c
@@ -227,7 +227,7 @@
 	prettyprint_ich_descriptors(cs, &desc);
 
 	pMAC = (uint8_t *) &buf[ICH_FREG_BASE(desc.region.reg3_base) >> 2];
-	if (len >= ICH_FREG_BASE(desc.region.reg3_base) + 5 && pMAC[0] != 0xff)
+	if (len >= ICH_FREG_BASE(desc.region.reg3_base) + 6 && pMAC[0] != 0xff)
 		printf("The MAC address might be at offset 0x%x: "
 		       "%02x:%02x:%02x:%02x:%02x:%02x\n",
 		       ICH_FREG_BASE(desc.region.reg3_base),