of_serial: Use linux/of_platform.h instead of asm

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>

drivers/serial/of_serial.c

@@ -13,8 +13,8 @@
 #include <linux/module.h>
 #include <linux/serial_core.h>
 #include <linux/serial_8250.h>
+#include <linux/of_platform.h>
 
-#include <asm/of_platform.h>
 #include <asm/prom.h>
 
 struct of_serial_info {