ARM: io: make iounmap() a simple macro

Defining iounmap() with arguments prevents it from being used as a
function pointer, causing platforms to work around this.  Instead,
define it to be a simple macro.

Do the same for __arch_io(re|un)map too.

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 815efa2..91be1f8 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -245,13 +245,13 @@
 #define ioremap_nocache(cookie,size)	__arm_ioremap(cookie, size, MT_DEVICE)
 #define ioremap_cached(cookie,size)	__arm_ioremap(cookie, size, MT_DEVICE_CACHED)
 #define ioremap_wc(cookie,size)		__arm_ioremap(cookie, size, MT_DEVICE_WC)
-#define iounmap(cookie)			__iounmap(cookie)
+#define iounmap				__iounmap
 #else
 #define ioremap(cookie,size)		__arch_ioremap((cookie), (size), MT_DEVICE)
 #define ioremap_nocache(cookie,size)	__arch_ioremap((cookie), (size), MT_DEVICE)
 #define ioremap_cached(cookie,size)	__arch_ioremap((cookie), (size), MT_DEVICE_CACHED)
 #define ioremap_wc(cookie,size)		__arch_ioremap((cookie), (size), MT_DEVICE_WC)
-#define iounmap(cookie)			__arch_iounmap(cookie)
+#define iounmap				__arch_iounmap
 #endif
 
 /*