hns3 udma: add mask for udma_reg_write

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


CVE: NA

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This patch add mask of value for udma_reg_write. The gcc of
an eariler version can be compiled smoothly.

Fixes: c256e44d ("hns3 udma:support loading and unloading of udma driver.")
Signed-off-by: Weibo Zhao <zhaoweibo3@huawei.com>