dp83640: Use generic ptp_msg_is_sync() function

Use generic ptp_msg_is_sync() function to avoid code duplication.
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/dp83640.c

@@ -970,17 +970,6 @@ static void decode_status_frame(struct dp83640_private *dp83640,
 	}
 }
 
-static int is_sync(struct sk_buff *skb, int type)
-{
-	struct ptp_header *hdr;
-
-	hdr = ptp_parse_header(skb, type);
-	if (!hdr)
-		return 0;
-
-	return ptp_get_msgtype(hdr, type) == PTP_MSGTYPE_SYNC;
-}
-
 static void dp83640_free_clocks(void)
 {
 	struct dp83640_clock *clock;
@@ -1396,7 +1385,7 @@ static void dp83640_txtstamp(struct mii_timestamper *mii_ts,
 	switch (dp83640->hwts_tx_en) {
 
 	case HWTSTAMP_TX_ONESTEP_SYNC:
-		if (is_sync(skb, type)) {
+		if (ptp_msg_is_sync(skb, type)) {
 			kfree_skb(skb);
 			return;
 		}