net: Move CDP out of net.c

Separate this functionality out of the net.c behemoth

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>

net/cdp.h

@@ -0,0 +1,20 @@
+/*
+ *	Copied from Linux Monitor (LiMon) - Networking.
+ *
+ *	Copyright 1994 - 2000 Neil Russell.
+ *	(See License)
+ *	Copyright 2000 Roland Borde
+ *	Copyright 2000 Paolo Scaffardi
+ *	Copyright 2000-2002 Wolfgang Denk, wd@denx.de
+ */
+
+#if defined(CONFIG_CMD_CDP)
+
+#ifndef __CDP_H__
+#define __CDP_H__
+
+void CDPStart(void);
+void CDPHandler(const uchar *pkt, unsigned len);
+
+#endif /* __CDP_H__ */
+#endif