ptp: do not explicitly set drvdata in ptp_clock_register()

We do not need explicitly call dev_set_drvdata(), as it is done for us by
device_create().

Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/ptp/ptp_clock.c

@@ -227,8 +227,6 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 	if (IS_ERR(ptp->dev))
 		goto no_device;
 
-	dev_set_drvdata(ptp->dev, ptp);
-
 	err = ptp_populate_sysfs(ptp);
 	if (err)
 		goto no_sysfs;