tipc: fix non-const printf format arguments

Fix warnings from current gcc about using non-const strings as printf
args in TIPC. Compile tested only (not a TIPC user).

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/bcast.h b/net/tipc/bcast.h
index 2f2d731..4c1771e 100644
--- a/net/tipc/bcast.h
+++ b/net/tipc/bcast.h
@@ -70,7 +70,7 @@
 
 struct tipc_node;
 
-extern char tipc_bclink_name[];
+extern const char tipc_bclink_name[];
 
 
 /**