!496 [sync] PR-448: LoongArch: fix some pci problems

Merge Pull Request from: @openeuler-sync-bot 
 

Origin pull request: 
https://gitee.com/openeuler/kernel/pulls/448 
 
fix some pci/pcie problems of LS7A.
After apply this PR and https://gitee.com/openeuler/kernel/pulls/476
, the following test passed:
1. boot 3A5000+7A2000 machine with integrated GPU
2. SUCCESS to login with tty0
3. echo mem >/sys/power/state
4. press powerbutton
5. machine resumed success 
 
Link:https://gitee.com/openeuler/kernel/pulls/496

 

Reviewed-by: Guo Dongtai <guodongtai@kylinos.cn>
Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>