igc: Rename IGC_TSYNCTXCTL_VALID macro

Rename the IGC_TSYNCTXCTL_VALID macro to IGC_TSYNCTXCTL_TXTT_0 so it
matches the datasheet.
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/igc/igc_defines.h

@@ -409,7 +409,7 @@
 #define IGC_IMIREXT_SIZE_BP	0x00001000  /* Packet size bypass */
 
 /* Time Sync Transmit Control bit definitions */
-#define IGC_TSYNCTXCTL_VALID			0x00000001  /* Tx timestamp valid */
+#define IGC_TSYNCTXCTL_TXTT_0			0x00000001  /* Tx timestamp reg 0 valid */
 #define IGC_TSYNCTXCTL_ENABLED			0x00000010  /* enable Tx timestamping */
 #define IGC_TSYNCTXCTL_MAX_ALLOWED_DLY_MASK	0x0000F000  /* max delay */
 #define IGC_TSYNCTXCTL_SYNC_COMP_ERR		0x20000000  /* sync err */

drivers/net/ethernet/intel/igc/igc_ptp.c

@@ -429,7 +429,7 @@ static void igc_ptp_tx_work(struct work_struct *work)
 	}
 
 	tsynctxctl = rd32(IGC_TSYNCTXCTL);
-	if (tsynctxctl & IGC_TSYNCTXCTL_VALID)
+	if (tsynctxctl & IGC_TSYNCTXCTL_TXTT_0)
 		igc_ptp_tx_hwtstamp(adapter);
 	else
 		/* reschedule to check later */