net: dsa: microchip: Correct initialization order for KSZ88x3 ports

Adjust the initialization sequence of KSZ88x3 switches to enable
802.1p priority control on Port 2 before configuring Port 1. This
change ensures the apptrust functionality on Port 1 operates
correctly, as it depends on the priority settings of Port 2. The
prior initialization sequence incorrectly configured Port 1 first,
which could lead to functional discrepancies.

Fixes: a1ea5771 ("net: dsa: microchip: dcb: add special handling for KSZ88X3 family")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Hariprasad Kelam <hkelam@marvell.com>
Acked-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Link: https://lore.kernel.org/r/20240517050121.2174412-1-o.rempel@pengutronix.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/microchip/ksz_dcb.c

@@ -805,5 +805,15 @@ int ksz_dcb_init(struct ksz_device *dev)
 	if (ret)
 		return ret;
 
+	/* Enable 802.1p priority control on Port 2 during switch initialization.
+	 * This setup is critical for the apptrust functionality on Port 1, which
+	 * relies on the priority settings of Port 2. Note: Port 1 is naturally
+	 * configured before Port 2, necessitating this configuration order.
+	 */
+	if (ksz_is_ksz88x3(dev))
+		return ksz_prmw8(dev, KSZ_PORT_2, KSZ8_REG_PORT_1_CTRL_0,
+				 KSZ8_PORT_802_1P_ENABLE,
+				 KSZ8_PORT_802_1P_ENABLE);
+
 	return 0;
 }