net: Add prototype for update_tftp

This function should be declared in net.h.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/include/net.h b/include/net.h
index 970d4d1..23fb947 100644
--- a/include/net.h
+++ b/include/net.h
@@ -695,6 +695,9 @@
 /* get a random source port */
 extern unsigned int random_port(void);
 
+/* Update U-Boot over TFTP */
+extern int update_tftp(ulong addr);
+
 /**********************************************************************/
 
 #endif /* __NET_H__ */