powerpc/mpc5200_wdt: use linux/of_platform.h instead of asm

Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

drivers/watchdog/mpc5200_wdt.c

@@ -4,7 +4,7 @@
 #include <linux/watchdog.h>
 #include <linux/io.h>
 #include <linux/spinlock.h>
-#include <asm/of_platform.h>
+#include <linux/of_platform.h>
 #include <asm/uaccess.h>
 #include <asm/mpc52xx.h>