i40e: Log info when PF is entering and leaving Allmulti mode.

Add log when PF is entering and leaving allmulti mode. The
change of PF state is visible in dmesg now. Without this commit,
entering and leaving allmulti mode is not logged in dmesg.
Signed-off-by: Czeslaw Zagorski <czeslawx.zagorski@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -2530,6 +2530,10 @@ int i40e_sync_vsi_filters(struct i40e_vsi *vsi)
 				 vsi_name,
 				 i40e_stat_str(hw, aq_ret),
 				 i40e_aq_str(hw, hw->aq.asq_last_status));
+		} else {
+			dev_info(&pf->pdev->dev, "%s is %s allmulti mode.\n",
+				 vsi->netdev->name,
+				 cur_multipromisc ? "entering" : "leaving");
 		}
 	}