!448 LoongArch: fix some pci problems

Merge Pull Request from: @Hongchen_Zhang 
 
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/448

 

Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com>
Reviewed-by: Guo Dongtai <guodongtai@kylinos.cn>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>