[NET]: Add macvlan driver

Add macvlan driver, which allows to create virtual ethernet devices
based on MAC address.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/if_macvlan.h

@@ -0,0 +1,9 @@
+#ifndef _LINUX_IF_MACVLAN_H
+#define _LINUX_IF_MACVLAN_H
+
+#ifdef __KERNEL__
+
+extern struct sk_buff *(*macvlan_handle_frame_hook)(struct sk_buff *);
+
+#endif /* __KERNEL__ */
+#endif /* _LINUX_IF_MACVLAN_H */