net: stmmac: Silence PTP init errors on hw without PTP

Logging a PTP error on hw which simply does not support PTP is not very
useful. Moreover this message gets logged on every if-up, and if there is
no cable inserted NetworkManager will re-try the ifup every 50 seconds.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -1635,7 +1635,7 @@ static int stmmac_hw_setup(struct net_device *dev)
 	stmmac_mmc_setup(priv);
 
 	ret = stmmac_init_ptp(priv);
-	if (ret)
+	if (ret && ret != -EOPNOTSUPP)
 		pr_warn("%s: failed PTP initialisation\n", __func__);
 
 #ifdef CONFIG_STMMAC_DEBUG_FS