RDMA/hns: Make some function static

Fixes the following sparse warnings:

drivers/infiniband/hw/hns/hns_roce_hw_v2.c:5822:5: warning:
 symbol 'hns_roce_v2_query_srq' was not declared. Should it be static?
drivers/infiniband/hw/hns/hns_roce_srq.c:158:6: warning:
 symbol 'hns_roce_srq_free' was not declared. Should it be static?
drivers/infiniband/hw/hns/hns_roce_srq.c:81:5: warning:
 symbol 'hns_roce_srq_alloc' was not declared. Should it be static?

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>