watchdog: mpc8xxx: allow to compile for MPC512x

The MPC5125 processor features a watchdog device that is identical to
the MPC8610 one. So allow to enable the driver for MPC512x kernel
configurations.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig

@@ -1344,7 +1344,7 @@ config MPC5200_WDT
 
 config 8xxx_WDT
 	tristate "MPC8xxx Platform Watchdog Timer"
-	depends on PPC_8xx || PPC_83xx || PPC_86xx
+	depends on PPC_8xx || PPC_83xx || PPC_86xx || PPC_MPC512x
 	select WATCHDOG_CORE
 	help
 	  This driver is for a SoC level watchdog that exists on some