arm: at91: gardena-smart-gateway-at91sam: 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: Eugen Hristev <eugen.hristev@microchip.com>
diff --git a/configs/gardena-smart-gateway-at91sam_defconfig b/configs/gardena-smart-gateway-at91sam_defconfig
index 577dceb..a25d378 100644
--- a/configs/gardena-smart-gateway-at91sam_defconfig
+++ b/configs/gardena-smart-gateway-at91sam_defconfig
@@ -36,6 +36,7 @@
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_MTD=y
 CONFIG_CMD_NAND=y
+CONFIG_CMD_WDT=y
 # CONFIG_CMD_SETEXPR is not set
 CONFIG_CMD_DHCP=y
 CONFIG_CMD_PING=y