bnxt_en: Fix race when modifying pause settings.

The driver was modified to not rely on rtnl lock to protect link
settings about 2 years ago.  The pause setting was missed when
making that change.  Fix it by acquiring link_lock mutex before
calling bnxt_hwrm_set_pause().

Fixes: e2dc9b6e ("bnxt_en: Don't use rtnl lock to protect link change logic in workqueue.")
Signed-off-by: NVasundhara Volam <vasundhara-v.volam@broadcom.com>
Reviewed-by: NEdwin Peer <edwin.peer@broadcom.com>
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

@@ -1765,8 +1765,11 @@ static int bnxt_set_pauseparam(struct net_device *dev,
 	if (epause->tx_pause)
 		link_info->req_flow_ctrl |= BNXT_LINK_PAUSE_TX;
 
-	if (netif_running(dev))
+	if (netif_running(dev)) {
+		mutex_lock(&bp->link_lock);
 		rc = bnxt_hwrm_set_pause(bp);
+		mutex_unlock(&bp->link_lock);
+	}
 	return rc;
 }