Kernel+AK: Separate out MACAddress and move it into AK

Author: https://github.com/alimpfard
Commit: 7d0bf9b5a9
Pull-request: https://github.com/SerenityOS/serenity/pull/1620
Reviewed-by: https://github.com/awesomekling
Reviewed-by: https://github.com/bcoles
Reviewed-by: https://github.com/bugaevc

Kernel/Net/EthernetFrameHeader.h

@@ -26,8 +26,8 @@
 
 #pragma once
 
+#include <AK/MACAddress.h>
 #include <AK/NetworkOrdered.h>
-#include <Kernel/Net/MACAddress.h>
 
 #pragma GCC diagnostic ignored "-Warray-bounds"