musb: io: only define read/write stubs if they're not defined yet

For those archs which don't provide read/write friends we
provide our own implementation so musb driver won't break
compilation.

This is temporary fix until a better solution comes from
upstream. Idealy, <linux/io.h> would provide those calls
if the architecture did not provide them yet. In that case
being possible to remove all those stubs from musb_io.h

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/musb/musb_io.h

@@ -37,7 +37,9 @@
 
 #include <linux/io.h>
 
-#ifndef	CONFIG_ARM
+#if !defined(CONFIG_ARM) && !defined(CONFIG_SUPERH) \
+	&& !defined(CONFIG_AVR32) && !defined(CONFIG_PPC32) \
+	&& !defined(CONFIG_PPC64)
 static inline void readsl(const void __iomem *addr, void *buf, int len)
 	{ insl((unsigned long)addr, buf, len); }
 static inline void readsw(const void __iomem *addr, void *buf, int len)