net: dsa: b53: Set correct number of ports in the DSA struct

stable inclusion
from stable-5.10.68
commit c361c955609a48d993f07caa93fdcc516de20849
bugzilla: 182671 https://gitee.com/openeuler/kernel/issues/I4EWUH

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c361c955609a48d993f07caa93fdcc516de20849



--------------------------------

[ Upstream commit d12e1c46 ]

Setting DSA_MAX_PORTS caused DSA to call b53 callbacks (e.g.
b53_disable_port() during dsa_register_switch()) for invalid
(non-existent) ports. That made b53 modify unrelated registers and is
one of reasons for a broken BCM5301x support.

This problem exists for years but DSA_MAX_PORTS usage has changed few
times. It seems the most accurate to reference commit dropping
dsa_switch_alloc() in the Fixes tag.

Fixes: 7e99e347 ("net: dsa: remove dsa_switch_alloc helper")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>