net: phy: dp83640: clear state after PTP registration failure

dp83640_probe() publishes its per-PHY state through phydev before
registering the PTP clock. If registration fails, the private data is
freed while phydev->mii_ts and phydev->priv still point to it, and
default_timestamp remains set.

Clear the published PHY state and reset the PTP clock pointer before
freeing the private data.

Cc: stable+noautosel@kernel.org # untested fix to a driver init path
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
Link: https://patch.msgid.link/20260811151345.73582-4-xuanqiang.luo@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/dp83640.c

@@ -1449,6 +1449,10 @@ static int dp83640_probe(struct phy_device *phydev)
 
 no_register:
 	clock->chosen = NULL;
+	clock->ptp_clock = NULL;
+	phydev->default_timestamp = false;
+	phydev->mii_ts = NULL;
+	phydev->priv = NULL;
 	kfree(dp83640);
 no_memory:
 	dp83640_clock_put(clock);