ixgbe: PTP get_ts_info missing software support

This patch corrects the ethtool get_ts_info functon which did not state that
software timestamping was supported, even though it is.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
CC: Stable <stable@vger.kernel.org> [3.5]
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c

@@ -2673,6 +2673,9 @@ static int ixgbe_get_ts_info(struct net_device *dev,
 	case ixgbe_mac_X540:
 	case ixgbe_mac_82599EB:
 		info->so_timestamping =
+			SOF_TIMESTAMPING_TX_SOFTWARE |
+			SOF_TIMESTAMPING_RX_SOFTWARE |
+			SOF_TIMESTAMPING_SOFTWARE |
 			SOF_TIMESTAMPING_TX_HARDWARE |
 			SOF_TIMESTAMPING_RX_HARDWARE |
 			SOF_TIMESTAMPING_RAW_HARDWARE;