mtd: s3c2410: Use <linux/io.h> instead of <asm/io.h>

Fixes the following checkpatch warning:
WARNING: Use #include <linux/io.h> instead of <asm/io.h>
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/s3c2410.c

@@ -32,6 +32,7 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
+#include <linux/io.h>
 #include <linux/ioport.h>
 #include <linux/platform_device.h>
 #include <linux/delay.h>
@@ -45,8 +46,6 @@
 #include <linux/mtd/nand_ecc.h>
 #include <linux/mtd/partitions.h>
 
-#include <asm/io.h>
-
 #include <plat/regs-nand.h>
 #include <plat/nand.h>