!1003 roh: Fix ROH multi-BD cmdq issue

Merge Pull Request from: @chenke1978 
 
When the ROH CMDQ processes multiple BDs, the operations are inconsistent
with those in the UM manual. As a result, the CMDQ parses unexpected return
values, interrupts the CMDQ processing process, and the ROH MIB statistics
query may fail.

This patch fix the process method of roh cmdq multiple BDs. 
 
Link:https://gitee.com/openeuler/kernel/pulls/1003

 

Reviewed-by: Ling Mingqiang <lingmingqiang@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>