hns3 udma: support POE mode.

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


CVE: NA

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This patch support POE mode of hns3-udma. POE mode is
a way that jfce was report to STARS directly.
In POE mode, doorbell address was passed to STARS so
that STARS can knock doorbell whenever it wants.

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