net: dsa: microchip: Add error handling for ksz_switch_macaddr_get()

Enhance the ksz_switch_macaddr_get() function to handle errors that may
occur during the call to ksz_write8(). Specifically, this update checks
the return value of ksz_write8(), which may fail if regmap ranges
validation is not passed and returns the error code.

Signed-off-by: Oleksij Rempel <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Reviewed-by: Vladimir Oltean <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/dsa/microchip/ksz_common.c

···
 	struct ksz_switch_macaddr *switch_macaddr;
 	struct ksz_device *dev = ds->priv;
 	const u16 *regs = dev->info->regs;
-	int i;
+	int i, ret;
 
 	/* Make sure concurrent MAC address changes are blocked */
 	ASSERT_RTNL();
···
 	dev->switch_macaddr = switch_macaddr;
 
 	/* Program the switch MAC address to hardware */
-	for (i = 0; i < ETH_ALEN; i++)
-		ksz_write8(dev, regs[REG_SW_MAC_ADDR] + i, addr[i]);
+	for (i = 0; i < ETH_ALEN; i++) {
+		ret = ksz_write8(dev, regs[REG_SW_MAC_ADDR] + i, addr[i]);
+		if (ret)
+			goto macaddr_drop;
+	}
 
 	return 0;
+
+macaddr_drop:
+	dev->switch_macaddr = NULL;
+	refcount_set(&switch_macaddr->refcount, 0);
+	kfree(switch_macaddr);
+
+	return ret;
 }
 
 void ksz_switch_macaddr_put(struct dsa_switch *ds)