NET: pass source IP address to packet handlers

This is needed for the upcoming TFTP server implementation.

This also simplifies PingHandler() and fixes rxhand_f documentation.

Signed-off-by: Luca Ceresoli <luca.ceresoli@comelit.it>
Cc: Wolfgang Denk <wd@denx.de>
Acked-by: Detlev Zundel <dzu@denx.de>
diff --git a/net/nfs.c b/net/nfs.c
index d11bb4c..f76f60d 100644
--- a/net/nfs.c
+++ b/net/nfs.c
@@ -580,7 +580,7 @@
 }
 
 static void
-NfsHandler (uchar *pkt, unsigned dest, unsigned src, unsigned len)
+NfsHandler(uchar *pkt, unsigned dest, IPaddr_t sip, unsigned src, unsigned len)
 {
 	int rlen;