bnxt_en: Adjust timer based on ethtool stats-block-usecs settings.

The driver gathers statistics using 2 mechanisms.  Some stats are DMA'ed
directly from hardware and others are polled from the driver's timer.
Currently, we only adjust the DMA frequency based on the ethtool
stats-block-usecs setting.  This patch adjusts the driver's timer
frequency as well to make everything consistent.
Signed-off-by: NMichael Chan <michael.chan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

@@ -112,6 +112,11 @@ static int bnxt_set_coalesce(struct net_device *dev,
 					      BNXT_MAX_STATS_COAL_TICKS);
 		stats_ticks = rounddown(stats_ticks, BNXT_MIN_STATS_COAL_TICKS);
 		bp->stats_coal_ticks = stats_ticks;
+		if (bp->stats_coal_ticks)
+			bp->current_interval =
+				bp->stats_coal_ticks * HZ / 1000000;
+		else
+			bp->current_interval = BNXT_TIMER_INTERVAL;
 		update_stats = true;
 	}