net: dsa: b53: Fix CPU port for 58xx devices

The 58xx devices (Northstar Plus) do actually have their CPU port wired
at port 8, it was unfortunately set to port 5 (B53_CPU_PORT_25) which is
incorrect, since that is the second possible management port.

Fixes: 991a36bb ("net: dsa: b53: Add support for BCM585xx/586xx/88312 integrated switch")
Reported-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/dsa/b53/b53_common.c

@@ -1764,7 +1764,7 @@ static const struct b53_chip_data b53_switch_chips[] = {
 		.vlans	= 4096,
 		.enabled_ports = 0x1ff,
 		.arl_entries = 4,
-		.cpu_port = B53_CPU_PORT_25,
+		.cpu_port = B53_CPU_PORT,
 		.vta_regs = B53_VTA_REGS,
 		.duplex_reg = B53_DUPLEX_STAT_GE,
 		.jumbo_pm_reg = B53_JUMBO_PORT_MASK,