!517 [sync] PR-510: LoongArch: fix dual-bridge machine can not work

Merge Pull Request from: @openeuler-sync-bot 
 

Origin pull request: 
https://gitee.com/openeuler/kernel/pulls/510 
 
After apply this PR, we can boot & reboot 3C5000+7A2000 dual-bridge machine normally. 
 
Link:https://gitee.com/openeuler/kernel/pulls/517

 

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