mips: mt7688: gardena-smart-gateway-mt7688: Enable CMD_WDT

This patch enables the "wdt" command, which is quite useful for watchdog
testing.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/configs/gardena-smart-gateway-mt7688-ram_defconfig b/configs/gardena-smart-gateway-mt7688-ram_defconfig
index e099506..c32aae4 100644
--- a/configs/gardena-smart-gateway-mt7688-ram_defconfig
+++ b/configs/gardena-smart-gateway-mt7688-ram_defconfig
@@ -26,6 +26,7 @@
 CONFIG_CMD_MTD=y
 CONFIG_CMD_SF=y
 CONFIG_CMD_SPI=y
+CONFIG_CMD_WDT=y
 CONFIG_CMD_DHCP=y
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y