ARM: UniPhier: replace <asm/io.h> with <linux/io.h>

In the Linux coding style, it is recommended to include <linux/io.h>
rather than <asm/io.h>.  Follow this trend.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/mach-uniphier/include/mach/sg-regs.h b/arch/arm/mach-uniphier/include/mach/sg-regs.h
index 63408d5..a65f058 100644
--- a/arch/arm/mach-uniphier/include/mach/sg-regs.h
+++ b/arch/arm/mach-uniphier/include/mach/sg-regs.h
@@ -1,7 +1,7 @@
 /*
  * UniPhier SG (SoC Glue) block registers
  *
- * Copyright (C) 2011-2015 Panasonic Corporation
+ * Copyright (C) 2011-2015 Masahiro Yamada <yamada.masahiro@socionext.com>
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */
@@ -108,7 +108,7 @@
 #else
 
 #include <linux/types.h>
-#include <asm/io.h>
+#include <linux/io.h>
 
 static inline void sg_set_pinsel(int n, int value)
 {