net: lan966x: Remove ptp traps in case the ptp is not enabled.

Lan966x is adding ptp traps to redirect the ptp frames to the CPU such
that the HW will not forward these frames anywhere. The issue is that in
case ptp is not enabled and the timestamping source is et to
HWTSTAMP_SOURCE_NETDEV then these traps would not be removed on the
error path.
Fix this by removing the traps in this case as they are not needed.

Fixes: 54e1ed69c40a ("net: lan966x: convert to ndo_hwtstamp_get() and ndo_hwtstamp_set()")
Suggested-by: Vladimir Oltean <[e-mail]>
Reviewed-by: Vladimir Oltean <[e-mail]>
Signed-off-by: Horatiu Vultur <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Paolo Abeni <[e-mail]>

drivers/net/ethernet/microchip/lan966x/lan966x_main.c

···
 	    cfg->source != HWTSTAMP_SOURCE_PHYLIB)
 		return -EOPNOTSUPP;
 
+	if (cfg->source == HWTSTAMP_SOURCE_NETDEV && !port->lan966x->ptp)
+		return -EOPNOTSUPP;
+
 	err = lan966x_ptp_setup_traps(port, cfg);
 	if (err)
 		return err;
 
 	if (cfg->source == HWTSTAMP_SOURCE_NETDEV) {
-		if (!port->lan966x->ptp)
-			return -EOPNOTSUPP;
-
 		err = lan966x_ptp_hwtstamp_set(port, cfg, extack);
 		if (err) {
 			lan966x_ptp_del_traps(port);