fib_trie: use seq_file_net rather than seq->private

Make fib_triestat_seq_show consistent with other /proc/net files and
use seq_file_net.

Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/fib_trie.c

@@ -2166,7 +2166,7 @@ static void fib_table_print(struct seq_file *seq, struct fib_table *tb)
 
 static int fib_triestat_seq_show(struct seq_file *seq, void *v)
 {
-	struct net *net = (struct net *)seq->private;
+	struct net *net = seq_file_net(seq);
 	unsigned int h;
 
 	seq_printf(seq,