watchdog: omap_wdt: convert to new watchdog core

Convert omap_wdt to new watchdog core. On OMAP boards, there are usually
multiple watchdogs. Since the new watchdog core supports multiple
watchdogs, all watchdog drivers used on OMAP should be converted.

The legacy watchdog device node is still created, so this should not
break existing users.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Tested-by: Jarkko Nikula <jarkko.nikula@jollamobile.com>
Tested-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig

@@ -232,6 +232,7 @@ config EP93XX_WATCHDOG
 config OMAP_WATCHDOG
 	tristate "OMAP Watchdog"
 	depends on ARCH_OMAP16XX || ARCH_OMAP2PLUS
+	select WATCHDOG_CORE
 	help
 	  Support for TI OMAP1610/OMAP1710/OMAP2420/OMAP3430/OMAP4430 watchdog.  Say 'Y'
 	  here to enable the OMAP1610/OMAP1710/OMAP2420/OMAP3430/OMAP4430 watchdog timer.