sh: Stub in P3 ioremap support for nommu parts.

p3_ioremap() references __ioremap() which is presently undefined on
nommu. This provides a trivial stub to fix the build up.

Signed-off-by: Paul Mundt <[e-mail]>

arch/sh/include/asm/io.h

···
 	return __ioremap(offset, size, flags);
 }
 #else
+#define __ioremap(offset, size, flags)		((void __iomem *)(offset))
 #define __ioremap_mode(offset, size, flags)	((void __iomem *)(offset))
 #define __iounmap(addr)				do { } while (0)
 #endif /* CONFIG_MMU */