bnxt_en: Allow statistics DMA to be configurable using ethtool -C.

The allowable range is 0.25 seconds to 1 second interval.  Default is
1 second.

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 18be62b..70b148a 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -3952,7 +3952,7 @@
 
 	bnxt_hwrm_cmd_hdr_init(bp, &req, HWRM_STAT_CTX_ALLOC, -1, -1);
 
-	req.update_period_ms = cpu_to_le32(1000);
+	req.update_period_ms = cpu_to_le32(bp->stats_coal_ticks / 1000);
 
 	mutex_lock(&bp->hwrm_cmd_lock);
 	for (i = 0; i < bp->cp_nr_rings; i++) {
@@ -5994,6 +5994,8 @@
 	bp->tx_coal_ticks_irq = 2;
 	bp->tx_coal_bufs_irq = 2;
 
+	bp->stats_coal_ticks = BNXT_DEF_STATS_COAL_TICKS;
+
 	init_timer(&bp->timer);
 	bp->timer.data = (unsigned long)bp;
 	bp->timer.function = bnxt_timer;