Fix warning differ in signedness in net/net.c and net/nfs.c
diff --git a/net/net.c b/net/net.c
index cde2680..c719bc4 100644
--- a/net/net.c
+++ b/net/net.c
@@ -94,7 +94,7 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#define ARP_TIMEOUT		5		/* Seconds before trying ARP again */
+#define ARP_TIMEOUT		5UL		/* Seconds before trying ARP again */
 #ifndef	CONFIG_NET_RETRY_COUNT
 # define ARP_TIMEOUT_COUNT	5		/* # of timeouts before giving up  */
 #else
@@ -589,7 +589,7 @@
 		return;
 	}
 #ifndef CONFIG_NET_MULTI
-	NetSetTimeout (10 * CFG_HZ, startAgainTimeout);
+	NetSetTimeout (10UL * CFG_HZ, startAgainTimeout);
 	NetSetHandler (startAgainHandler);
 #else	/* !CONFIG_NET_MULTI*/
 	eth_halt ();
@@ -598,7 +598,7 @@
 	if (NetRestartWrap) {
 		NetRestartWrap = 0;
 		if (NetDevExists && !once) {
-			NetSetTimeout (10 * CFG_HZ, startAgainTimeout);
+			NetSetTimeout (10UL * CFG_HZ, startAgainTimeout);
 			NetSetHandler (startAgainHandler);
 		} else {
 			NetState = NETLOOP_FAIL;
@@ -774,7 +774,7 @@
 #if defined(CONFIG_NET_MULTI)
 	printf ("Using %s device\n", eth_get_name());
 #endif	/* CONFIG_NET_MULTI */
-	NetSetTimeout (10 * CFG_HZ, PingTimeout);
+	NetSetTimeout (10UL * CFG_HZ, PingTimeout);
 	NetSetHandler (PingHandler);
 
 	PingSend();