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

This patch changes the driver to use ns_to_timespec64() and
timespec64_to_ns() 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/freescale/fec_ptp.c

@@ -395,15 +395,13 @@ static int fec_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
 	struct fec_enet_private *adapter =
 	    container_of(ptp, struct fec_enet_private, ptp_caps);
 	u64 ns;
-	u32 remainder;
 	unsigned long flags;
 
 	spin_lock_irqsave(&adapter->tmreg_lock, flags);
 	ns = timecounter_read(&adapter->tc);
 	spin_unlock_irqrestore(&adapter->tmreg_lock, flags);
 
-	ts->tv_sec = div_u64_rem(ns, 1000000000ULL, &remainder);
-	ts->tv_nsec = remainder;
+	*ts = ns_to_timespec64(ns);
 
 	return 0;
 }
@@ -433,8 +431,7 @@ static int fec_ptp_settime(struct ptp_clock_info *ptp,
 		return -EINVAL;
 	}
 
-	ns = ts->tv_sec * 1000000000ULL;
-	ns += ts->tv_nsec;
+	ns = timespec64_to_ns(ts);
 	/* Get the timer value based on timestamp.
 	 * Update the counter with the masked value.
 	 */