!510 LoongArch: fix dual-bridge machine can not work

Merge Pull Request from: @Hongchen_Zhang 
 
After apply this PR, we can boot & reboot 3C5000+7A2000 dual-bridge machine normally. 
 
Link:https://gitee.com/openeuler/kernel/pulls/510

 

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