ptp: tg3: 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/broadcom/tg3.c

@@ -6220,16 +6220,14 @@ static int tg3_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 static int tg3_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
 {
 	u64 ns;
-	u32 remainder;
 	struct tg3 *tp = container_of(ptp, struct tg3, ptp_info);
 
 	tg3_full_lock(tp, 0);
 	ns = tg3_refclk_read(tp);
 	ns += tp->ptp_adjust;
 	tg3_full_unlock(tp);
 
-	ts->tv_sec = div_u64_rem(ns, 1000000000, &remainder);
-	ts->tv_nsec = remainder;
+	*ts = ns_to_timespec64(ns);
 
 	return 0;
 }