net/mlx4_core: Replace sscanf() with kstrtoint()

It is not safe to use sscanf.
Signed-off-by: Dotan Barak <dotanb@dev.mellanox.com>
Signed-off-by: Vladimir Sokolovsky <vlad@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/main.c

@@ -839,11 +839,11 @@ static ssize_t set_port_ib_mtu(struct device *dev,
 		return -EINVAL;
 	}
 
-	err = sscanf(buf, "%d", &mtu);
-	if (err > 0)
+	err = kstrtoint(buf, 0, &mtu);
+	if (!err)
 		ibta_mtu = int_to_ibta_mtu(mtu);
 
-	if (err <= 0 || ibta_mtu < 0) {
+	if (err || ibta_mtu < 0) {
 		mlx4_err(mdev, "%s is invalid IBTA mtu\n", buf);
 		return -EINVAL;
 	}