[ARM] Add a common typesafe __io implementation

As Al did for Versatile in 2ad4f86b60b649fd7428265c08d73a3bd360c81b,
add a typesafe __io implementation for platforms to use.  Convert
platforms to use this new simple typesafe implementation.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index a809445..d2a59cf 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -80,6 +80,14 @@
 extern void __readwrite_bug(const char *fn);
 
 /*
+ * A typesafe __io() helper
+ */
+static inline void __iomem *__typesafe_io(unsigned long addr)
+{
+	return (void __iomem *)addr;
+}
+
+/*
  * Now, pick up the machine-defined IO definitions
  */
 #include <mach/io.h>