!4024 udma: add mailbox description printing.

Merge Pull Request from: @zhaoweibo3 
 
driver inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8V1IQ


CVE: NA

[content]
This patch add print of mailbox if dfx_switch is on.
The print of mailbox description is key information
of bug locating.

Fixes: c256e44d ("hns3 udma: support loading and unloading of udma driver.")
Signed-off-by: Weibo Zhao <zhaoweibo3@huawei.com>
 
Link:https://gitee.com/openeuler/kernel/pulls/4024

 

Reviewed-by: Chunzhi Hu <huchunzhi@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>