net: dsa: microchip: fix PTP config failure when using multiple ports

When performing the port_hwtstamp_set operation, ptp_schedule_worker()
will be called if hardware timestamoing is enabled on any of the ports.
When using multiple ports for PTP, port_hwtstamp_set is executed for
each port. When called for the first time ptp_schedule_worker() returns
0. On subsequent calls it returns 1, indicating the worker is already
scheduled. Currently the ksz driver treats 1 as an error and fails to
complete the port_hwtstamp_set operation, thus leaving the timestamping
configuration for those ports unchanged.

This patch fixes this by ignoring the ptp_schedule_worker() return
value.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/7aae307a-35ca-4209-a850-7b2749d40f90@martin-whitaker.me.uk
Fixes: bb01ad30 ("net: dsa: microchip: ptp: manipulating absolute time using ptp hw clock")
Signed-off-by: Martin Whitaker <foss@martin-whitaker.me.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Link: https://patch.msgid.link/20240817094141.3332-1-foss@martin-whitaker.me.ukSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/microchip/ksz_ptp.c

@@ -266,7 +266,6 @@ static int ksz_ptp_enable_mode(struct ksz_device *dev)
 	struct ksz_port *prt;
 	struct dsa_port *dp;
 	bool tag_en = false;
-	int ret;
 
 	dsa_switch_for_each_user_port(dp, dev->ds) {
 		prt = &dev->ports[dp->index];
@@ -277,9 +276,7 @@ static int ksz_ptp_enable_mode(struct ksz_device *dev)
 	}
 
 	if (tag_en) {
-		ret = ptp_schedule_worker(ptp_data->clock, 0);
-		if (ret)
-			return ret;
+		ptp_schedule_worker(ptp_data->clock, 0);
 	} else {
 		ptp_cancel_worker_sync(ptp_data->clock);
 	}