net: Make static

Sparse asked whether these could be static.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rxrpc/ar-security.c b/net/rxrpc/ar-security.c
index 60d1d36..dc62920e 100644
--- a/net/rxrpc/ar-security.c
+++ b/net/rxrpc/ar-security.c
@@ -40,7 +40,7 @@
 /*
  * look up an rxrpc security module
  */
-struct rxrpc_security *rxrpc_security_lookup(u8 security_index)
+static struct rxrpc_security *rxrpc_security_lookup(u8 security_index)
 {
 	struct rxrpc_security *sec = NULL;