net/9p: add privport option to 9p tcp transport

If the privport option is specified, the tcp transport binds local
address to a reserved port before connecting to the 9p server.

In some cases when 9P AUTH cannot be implemented, this is better than
nothing.

Signed-off-by: Jim Garlick <garlick@llnl.gov>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/include/net/9p/transport.h b/include/net/9p/transport.h
index adcbb20..9a36d92 100644
--- a/include/net/9p/transport.h
+++ b/include/net/9p/transport.h
@@ -26,6 +26,9 @@
 #ifndef NET_9P_TRANSPORT_H
 #define NET_9P_TRANSPORT_H
 
+#define P9_DEF_MIN_RESVPORT	(665U)
+#define P9_DEF_MAX_RESVPORT	(1023U)
+
 /**
  * struct p9_trans_module - transport module interface
  * @list: used to maintain a list of currently available transports