hns3 udma: create and destroy u-context

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


CVE: NA

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This patch is code for create and destroy u-context.
Context is isolated by process. Uar in u-context
contains doorbell address and direct wqe address.

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