l2tp: move from strlcpy with unused retval to strscpy

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=[e-mail]/
Signed-off-by: Wolfram Sang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/l2tp/l2tp_eth.c

···
 	int rc;
 
 	if (cfg->ifname) {
-		strlcpy(name, cfg->ifname, IFNAMSIZ);
+		strscpy(name, cfg->ifname, IFNAMSIZ);
 		name_assign_type = NET_NAME_USER;
 	} else {
 		strcpy(name, L2TP_ETH_DEV_NAME);
···
 		return rc;
 	}
 
-	strlcpy(session->ifname, dev->name, IFNAMSIZ);
+	strscpy(session->ifname, dev->name, IFNAMSIZ);
 	rcu_assign_pointer(spriv->dev, dev);
 
 	rtnl_unlock();