ptp: mlx4: use helpers for converting ns to timespec.

This patch changes the driver to use ns_to_timespec64() instead of
open coding the same logic.

Compile tested only.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -170,15 +170,13 @@ static int mlx4_en_phc_gettime(struct ptp_clock_info *ptp,
 	struct mlx4_en_dev *mdev = container_of(ptp, struct mlx4_en_dev,
 						ptp_clock_info);
 	unsigned long flags;
-	u32 remainder;
 	u64 ns;
 
 	write_lock_irqsave(&mdev->clock_lock, flags);
 	ns = timecounter_read(&mdev->clock);
 	write_unlock_irqrestore(&mdev->clock_lock, flags);
 
-	ts->tv_sec = div_u64_rem(ns, NSEC_PER_SEC, &remainder);
-	ts->tv_nsec = remainder;
+	*ts = ns_to_timespec64(ns);
 
 	return 0;
 }