watchdog: kconfig: Enable designware for rk3399

Enable designware watchdog driver for rk3399 if WDT defined.

Cc: Marek Vasut <marex@denx.de>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 6cafd24..bf06180 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -49,6 +49,7 @@
 config DESIGNWARE_WATCHDOG
 	bool "Designware watchdog timer support"
 	select HW_WATCHDOG if !WDT
+	default y if WDT && ROCKCHIP_RK3399
 	help
 	  Enable this to support Designware Watchdog Timer IP, present e.g.
 	  on Altera SoCFPGA SoCs.