generic: rtl8367b: make it possible to specify cpu_port via DT

This patch adds the feature to parse the existing cpu_port DT
property, which is used to specify which port is the cpu port
of the switch.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

target/linux/generic/files/drivers/net/phy/rtl8367b.c

@@ -1401,7 +1401,7 @@ static int rtl8367b_switch_init(struct rtl8366_smi *smi)
 	int err;
 
 	dev->name = "RTL8367B";
-	dev->cpu_port = RTL8367B_CPU_PORT_NUM;
+	dev->cpu_port = smi->cpu_port;
 	dev->ports = RTL8367B_NUM_PORTS;
 	dev->vlans = RTL8367B_NUM_VIDS;
 	dev->ops = &rtl8367b_sw_ops;
@@ -1534,8 +1534,10 @@ static int  rtl8367b_probe(struct platform_device *pdev)
 	smi->cmd_read = 0xb9;
 	smi->cmd_write = 0xb8;
 	smi->ops = &rtl8367b_smi_ops;
-	smi->cpu_port = RTL8367B_CPU_PORT_NUM;
 	smi->num_ports = RTL8367B_NUM_PORTS;
+	if (of_property_read_u32(pdev->dev.of_node, "cpu_port", &smi->cpu_port)
+	    || smi->cpu_port >= smi->num_ports)
+		smi->cpu_port = RTL8367B_CPU_PORT_NUM;
 	smi->num_vlan_mc = RTL8367B_NUM_VLANS;
 	smi->mib_counters = rtl8367b_mib_counters;
 	smi->num_mib_counters = ARRAY_SIZE(rtl8367b_mib_counters);