l2tp: use IS_ENABLED() instead of checking for built-in or module

The IS_ENABLED() macro checks if a Kconfig symbol has been enabled either
built-in or as a module, use that macro instead of open coding the same.

Using the macro makes the code more readable by helping abstract away some
of the Kconfig built-in and module enable details.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/l2tp/l2tp_core.h

@@ -139,7 +139,7 @@ struct l2tp_session {
 	void (*session_close)(struct l2tp_session *session);
 	void (*ref)(struct l2tp_session *session);
 	void (*deref)(struct l2tp_session *session);
-#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
+#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
 	void (*show)(struct seq_file *m, void *priv);
 #endif
 	uint8_t			priv[0];	/* private data */

net/l2tp/l2tp_eth.c

@@ -195,7 +195,7 @@ static void l2tp_eth_delete(struct l2tp_session *session)
 	}
 }
 
-#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
+#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
 static void l2tp_eth_show(struct seq_file *m, void *arg)
 {
 	struct l2tp_session *session = arg;
@@ -268,7 +268,7 @@ static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 p
 	priv->tunnel_sock = tunnel->sock;
 	session->recv_skb = l2tp_eth_dev_recv;
 	session->session_close = l2tp_eth_delete;
-#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
+#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
 	session->show = l2tp_eth_show;
 #endif
 

net/l2tp/l2tp_ppp.c

@@ -552,7 +552,7 @@ static int pppol2tp_create(struct net *net, struct socket *sock, int kern)
 	return error;
 }
 
-#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
+#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
 static void pppol2tp_show(struct seq_file *m, void *arg)
 {
 	struct l2tp_session *session = arg;
@@ -723,7 +723,7 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 
 	session->recv_skb	= pppol2tp_recv;
 	session->session_close	= pppol2tp_session_close;
-#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
+#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
 	session->show		= pppol2tp_show;
 #endif