watchdog: imx2_wdt: convert to watchdog core api

Convert the imx2_wdt driver to the new watchdog core api.
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Cc: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig

@@ -379,6 +379,7 @@ config IMX2_WDT
 	tristate "IMX2+ Watchdog"
 	depends on ARCH_MXC
 	select REGMAP_MMIO
+	select WATCHDOG_CORE
 	help
 	  This is the driver for the hardware watchdog
 	  on the Freescale IMX2 and later processors.