watchdog: mpc8xxx_wdt convert to watchdog core

Convert mpc8xxx_wdt.c to the new watchdog API.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 833ebe6..8cb4f3d 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1202,6 +1202,7 @@
 config 8xxx_WDT
 	tristate "MPC8xxx Platform Watchdog Timer"
 	depends on PPC_8xx || PPC_83xx || PPC_86xx
+	select WATCHDOG_CORE
 	help
 	  This driver is for a SoC level watchdog that exists on some
 	  Freescale PowerPC processors. So far this driver supports: