gianfar: Support the get_ts_info ethtool method.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/freescale/gianfar_ptp.c b/drivers/net/ethernet/freescale/gianfar_ptp.c
index 5fd620b..c08e5d4 100644
--- a/drivers/net/ethernet/freescale/gianfar_ptp.c
+++ b/drivers/net/ethernet/freescale/gianfar_ptp.c
@@ -515,6 +515,7 @@
 		err = PTR_ERR(etsects->clock);
 		goto no_clock;
 	}
+	gfar_phc_clock = ptp_clock_index(etsects->clock);
 
 	dev_set_drvdata(&dev->dev, etsects);
 
@@ -538,6 +539,7 @@
 	gfar_write(&etsects->regs->tmr_temask, 0);
 	gfar_write(&etsects->regs->tmr_ctrl,   0);
 
+	gfar_phc_clock = -1;
 	ptp_clock_unregister(etsects->clock);
 	iounmap(etsects->regs);
 	release_resource(etsects->rsrc);