watchdog: Fix build failure with OF changes

commit 61c7a080 ( of: Always use
'struct device.of_node' to get device node pointer.) missed
drivers/watchdog/mpc8xxx_wdt.c. This patch fixes it
Signed-off-by: NMichael Guntsche <mike@it-loops.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

drivers/watchdog/mpc8xxx_wdt.c

@@ -189,7 +189,7 @@ static int __devinit mpc8xxx_wdt_probe(struct of_device *ofdev,
 				       const struct of_device_id *match)
 {
 	int ret;
-	struct device_node *np = ofdev->node;
+	struct device_node *np = ofdev->dev.of_node;
 	struct mpc8xxx_wdt_type *wdt_type = match->data;
 	u32 freq = fsl_get_sys_freq();
 	bool enabled;