watchdog: Convert jz4740_wdt driver to watchdog core

This patch converts jz4740_wdt driver to use watchdog core APIs.
Also use devm_* APIs to save a few error handling code.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 7e9e8f4..d5531fb 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -955,6 +955,7 @@
 config JZ4740_WDT
 	tristate "Ingenic jz4740 SoC hardware watchdog"
 	depends on MACH_JZ4740
+	select WATCHDOG_CORE
 	help
 	  Hardware driver for the built-in watchdog timer on Ingenic jz4740 SoCs.