ixgbe: Cleanup PCIe bus speed info

PCIe connections should be expressed as GT/s (GigaTransfers per second)
instead of the current Gb/s (Gigabits per second).  In addition, it is
incorrect because (due to PCIe gen 1 & 2 having a 20% overhead) the
actually data rate, when expressed in Gb/s, is only 80% of the rate of
GT/s.
Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Tested-by: Evan Swanson <evan.swanson@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ixgbe/ixgbe_main.c

@@ -7469,8 +7469,8 @@ static int __devinit ixgbe_probe(struct pci_dev *pdev,
 
 	/* print bus type/speed/width info */
 	e_dev_info("(PCI Express:%s:%s) %pM\n",
-		   (hw->bus.speed == ixgbe_bus_speed_5000 ? "5.0Gb/s" :
-		    hw->bus.speed == ixgbe_bus_speed_2500 ? "2.5Gb/s" :
+		   (hw->bus.speed == ixgbe_bus_speed_5000 ? "5.0GT/s" :
+		    hw->bus.speed == ixgbe_bus_speed_2500 ? "2.5GT/s" :
 		    "Unknown"),
 		   (hw->bus.width == ixgbe_bus_width_pcie_x8 ? "Width x8" :
 		    hw->bus.width == ixgbe_bus_width_pcie_x4 ? "Width x4" :