Enable HW watchdog before fast-reboot (#977)

scripts/fast-reboot

@@ -13,6 +13,7 @@ STRICT=no
 REBOOT_METHOD="/sbin/kexec -e"
 ASSISTANT_IP_LIST=""
 ASSISTANT_SCRIPT="/usr/bin/neighbor_advertiser"
+WATCHDOG_UTIL="/usr/bin/watchdogutil"
 DEVPATH="/usr/share/sonic/device"
 PLATFORM=$(sonic-cfggen -H -v DEVICE_METADATA.localhost.platform)
 PLATFORM_PLUGIN="${REBOOT_TYPE}_plugin"
@@ -593,6 +594,12 @@ if [ -x ${DEVPATH}/${PLATFORM}/${PLATFORM_PLUGIN} ]; then
     ${DEVPATH}/${PLATFORM}/${PLATFORM_PLUGIN}
 fi
 
+# Enable Watchdog Timer
+if [ -x ${WATCHDOG_UTIL} ]; then
+    debug "Enabling Watchdog before ${REBOOT_TYPE}"
+    ${WATCHDOG_UTIL} arm
+fi
+
 # Reboot: explicity call Linux native reboot under sbin
 debug "Rebooting with ${REBOOT_METHOD} to ${NEXT_SONIC_IMAGE} ..."
 exec ${REBOOT_METHOD}