watchdog: Convert max63xx_wdt driver to watchdog framework

This patch converts max63xx_wdt driver to watchdog framework.
Also use devm_* APIs to save a few error handling code.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index c83a83f..8f5c317 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -330,6 +330,7 @@
 config MAX63XX_WATCHDOG
 	tristate "Max63xx watchdog"
 	depends on ARM && HAS_IOMEM
+	select WATCHDOG_CORE
 	help
 	  Support for memory mapped max63{69,70,71,72,73,74} watchdog timer.