mfd: Include <linux/io.h> instead of <asm/io.h>

As warned by checkpatch.pl, use #include <linux/io.h> instead of <asm/io.h>

Signed-off-by: Axel Lin <[e-mail]>
Acked-by: Ben Dooks <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>

drivers/mfd/sm501.c

···
 #include <linux/sm501-regs.h>
 #include <linux/serial_8250.h>
 
-#include <asm/io.h>
+#include <linux/io.h>
 
 struct sm501_device {
 	struct list_head		list;