e1000e: Alert the user that C-states will be disabled by enabling jumbo frames

I personally spent a long time trying to decypher why my CPU would not
reach deeper C-states. Let's just tell the next user what's going on.

Signed-off-by: Matt Turner <matt.turner@intel.com>
Acked-by: Shannon Nelson <shannon.nelson@oracle.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/e1000e/netdev.c

@@ -3306,6 +3306,8 @@ static void e1000_configure_rx(struct e1000_adapter *adapter)
 			ew32(RXDCTL(0), rxdctl | 0x3 | BIT(8));
 		}
 
+		dev_info(&adapter->pdev->dev,
+			 "Some CPU C-states have been disabled in order to enable jumbo frames\n");
 		pm_qos_update_request(&adapter->pm_qos_req, lat);
 	} else {
 		pm_qos_update_request(&adapter->pm_qos_req,