PCI: aardvark: Fix preserving PCI_EXP_RTCTL_CRSSVE flag on emulated bridge

stable inclusion
from stable-5.10.80
commit bea3213f191a36e34e652c0d964fc3977886a408
bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bea3213f191a36e34e652c0d964fc3977886a408

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[ Upstream commit d419052b ]

Commit 43f5c77b ("PCI: aardvark: Fix reporting CRS value") started
using CRSSVE flag for handling CRS responses.

PCI_EXP_RTCTL_CRSSVE flag is stored only in emulated config space buffer
and there is handler for PCI_EXP_RTCTL register. So every read operation
from config space automatically clears CRSSVE flag as it is not defined in
PCI_EXP_RTCTL read handler.

Fix this by reading current CRSSVE bit flag from emulated space buffer and
appending it to PCI_EXP_RTCTL read response.

Link: https://lore.kernel.org/r/20211005180952.6812-5-kabel@kernel.org


Fixes: 43f5c77b ("PCI: aardvark: Fix reporting CRS value")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Reviewed-by: Weilong Chen <chenweilong@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>