ixgbe: Fix overwriting of rx_mtrl in ixgbe_ptp_hwtstamp_ioctl

This patch corrects a bug introduced by commit f3444d8b. The rxmtrl value for
the UDP port to timestamp on was moved above the switch statement, but was
overwritten to 0 if the ioctl selected one of the V1 filters.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

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

@@ -660,11 +660,11 @@ int ixgbe_ptp_hwtstamp_ioctl(struct ixgbe_adapter *adapter,
 		break;
 	case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
 		tsync_rx_ctl |= IXGBE_TSYNCRXCTL_TYPE_L4_V1;
-		tsync_rx_mtrl = IXGBE_RXMTRL_V1_SYNC_MSG;
+		tsync_rx_mtrl |= IXGBE_RXMTRL_V1_SYNC_MSG;
 		break;
 	case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ:
 		tsync_rx_ctl |= IXGBE_TSYNCRXCTL_TYPE_L4_V1;
-		tsync_rx_mtrl = IXGBE_RXMTRL_V1_DELAY_REQ_MSG;
+		tsync_rx_mtrl |= IXGBE_RXMTRL_V1_DELAY_REQ_MSG;
 		break;
 	case HWTSTAMP_FILTER_PTP_V2_EVENT:
 	case HWTSTAMP_FILTER_PTP_V2_L2_EVENT: