net: cosmetic: Un-typedef IP_t

Rename IP header related things to IP_UDP. The existing definition
of IP_t includes UDP header, so name it to accurately describe the
structure.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/net/nfs.c b/net/nfs.c
index 54f56c4..b6188fe 100644
--- a/net/nfs.c
+++ b/net/nfs.c
@@ -189,7 +189,7 @@
 
 	pktlen = (char *)p + datalen*sizeof(uint32_t) - (char *)&pkt;
 
-	memcpy((char *)NetTxPacket + NetEthHdrSize() + IP_HDR_SIZE,
+	memcpy((char *)NetTxPacket + NetEthHdrSize() + IP_UDP_HDR_SIZE,
 		(char *)&pkt, pktlen);
 
 	if (rpc_prog == PROG_PORTMAP)