RDMA/hns: Simplify the function config_eqc()

Use "hr_reg_write" replace "roce_set_filed".

Link: https://lore.kernel.org/r/1617354454-47840-9-git-send-email-liweihang@huawei.com
Signed-off-by: Yixing Liu <liuyixing1@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>