SUNRPC: Convert gss_ctx_lock to an RCU lock

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/auth_gss.h b/include/linux/sunrpc/auth_gss.h
index 0bd1d06..67658e1 100644
--- a/include/linux/sunrpc/auth_gss.h
+++ b/include/linux/sunrpc/auth_gss.h
@@ -75,6 +75,7 @@
 	struct xdr_netobj	gc_wire_ctx;
 	u32			gc_win;
 	unsigned long		gc_expiry;
+	struct rcu_head		gc_rcu;
 };
 
 struct gss_upcall_msg;