amdfwtool: Clear the whole byte of EFS_GEN

Change-Id: I434e031e906f73362b1e920e034fa15a8d078ab2
Signed-off-by: Zheng Bao <fishbaozi@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63138
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/util/amdfwtool/amdfwtool.c b/util/amdfwtool/amdfwtool.c
index f0fdd0a..0cfe307 100644
--- a/util/amdfwtool/amdfwtool.c
+++ b/util/amdfwtool/amdfwtool.c
@@ -1785,6 +1785,7 @@
 	amd_romsig->imc_entry = 0;
 	amd_romsig->gec_entry = 0;
 	amd_romsig->xhci_entry = 0;
+	amd_romsig->efs_gen.reserved = 0;
 
 	if (soc_id != PLATFORM_UNKNOWN) {
 		retval = set_efs_table(soc_id, amd_romsig, efs_spi_readmode,