watchdog: orion_wdt: Convert driver to watchdog core

Convert orion_wdt driver to use watchdog framework API.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 277ecbc..46e258c 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -279,6 +279,7 @@
 config ORION_WATCHDOG
 	tristate "Orion watchdog"
 	depends on ARCH_ORION5X || ARCH_KIRKWOOD
+	select WATCHDOG_CORE
 	help
 	  Say Y here if to include support for the watchdog timer
 	  in the Marvell Orion5x and Kirkwood ARM SoCs.