ptp: remember the adjusted frequency

This patch adds a field to the representation of a PTP hardware clock in
order to remember the frequency adjustment value dialed by the user.

Adding this field will let us answer queries in the manner of adjtimex
in a follow on patch.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 966875d..67e628e 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -147,6 +147,7 @@
 	} else if (tx->modes & ADJ_FREQUENCY) {
 
 		err = ops->adjfreq(ops, scaled_ppm_to_ppb(tx->freq));
+		ptp->dialed_frequency = tx->freq;
 	}
 
 	return err;