[NETFILTER]: nf_log: minor cleanups

- rename nf_logging to nf_loggers since its an array of registered loggers

- rename nf_log_unregister_logger() to nf_log_unregister() to make it
  symetrical to nf_log_register() and convert all users

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index c47e7e2..edbb8ff 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -1077,7 +1077,7 @@
 
 static void __exit nfnetlink_log_fini(void)
 {
-	nf_log_unregister_logger(&nfulnl_logger);
+	nf_log_unregister(&nfulnl_logger);
 #ifdef CONFIG_PROC_FS
 	remove_proc_entry("nfnetlink_log", proc_net_netfilter);
 #endif