MIPS: Octeon: Add PCIe link status check

mainline inclusion
from mainline-v6.10-rc1
commit 29b83a64df3b42c88c0338696feb6fdcd7f1f3b7
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IACSM3
CVE: CVE-2024-40968

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=29b83a64df3b42c88c0338696feb6fdcd7f1f3b7



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The standard PCIe configuration read-write interface is used to
access the configuration space of the peripheral PCIe devices
of the mips processor after the PCIe link surprise down, it can
generate kernel panic caused by "Data bus error". So it is
necessary to add PCIe link status check for system protection.
When the PCIe link is down or in training, assigning a value
of 0 to the configuration address can prevent read-write behavior
to the configuration space of peripheral PCIe devices, thereby
preventing kernel panic.

Signed-off-by: Songyang Li <leesongyang@outlook.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Liao Chen <liaochen4@huawei.com>