watchdog: at91sam9_wdt: Convert to use the watchdog framework

According to Documentation/watchdog/convert_drivers_to_kernel_api.txt,
remove the file_operations struct, miscdevice, and obsolete includes

Since the at91sam watchdog inherent characteristics, add the watchdog
operations: at91wdt_start, at91wdt_stop and at91wdt_ping.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index f3aae8c..83ac1f7 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -125,6 +125,7 @@
 config AT91SAM9X_WATCHDOG
 	tristate "AT91SAM9X / AT91CAP9 watchdog"
 	depends on ARCH_AT91 && !ARCH_AT91RM9200
+	select WATCHDOG_CORE
 	help
 	  Watchdog timer embedded into AT91SAM9X and AT91CAP9 chips. This will
 	  reboot your system when the timeout is reached.