hns3 udma: add function clear when ko rmmod

driver inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I85R2F


CVE: NA

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When rmmod ko and hw exit, function clear should
be done. Driver post a function clear command to
hardware to clean resource in function.

Signed-off-by: Weibo Zhao <zhaoweibo3@huawei.com>