sandbox: add memset_io(..), memcpy_fromio(..) and memcpy_toio(..)

These functions could be used by drivers.

Signed-off-by: Christian GMEINER <christian.GMEINER@bachmann.info>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/include/asm/io.h b/arch/sandbox/include/asm/io.h
index 81b7750..2a350a8 100644
--- a/arch/sandbox/include/asm/io.h
+++ b/arch/sandbox/include/asm/io.h
@@ -173,6 +173,18 @@
 {
 }
 
+static inline void memset_io(volatile void *addr, unsigned char val, int count)
+{
+}
+
+static inline void memcpy_fromio(void *dst, const volatile void *src, int count)
+{
+}
+
+static inline void memcpy_toio(volatile void *dst, const void *src, int count)
+{
+}
+
 #define insw(port, buf, ns)		_insw((u16 *)port, buf, ns)
 #define outsw(port, buf, ns)		_outsw((u16 *)port, buf, ns)