RDMA/hns: make various function static, fixes warnings

The functions hns_roce_table_mhop_get, hns_roce_table_mhop_put,
hns_roce_cleanup_mhop_hem_table,  hns_roce_v1_post_mbox,
hns_roce_cmq_setup_basic_desc, hns_roce_cmq_send,
hns_roce_cmq_query_hw_info are all local to the source and do
not need to be in global scope, so make them static.

Cleans up sparse warnings:
symbol 'hns_roce_table_mhop_get' was not declared. Should it be static?
symbol 'hns_roce_table_mhop_put' was not declared. Should it be static?
symbol 'hns_roce_cleanup_mhop_hem_table' was not declared. Should it be
static?
symbol 'hns_roce_v1_post_mbox' was not declared. Should it be static?
symbol 'hns_roce_cmq_setup_basic_desc' was not declared. Should it be
static?
symbol 'hns_roce_cmq_send' was not declared. Should it be static?
symbol 'hns_roce_cmq_query_hw_info' was not declared. Should it be static?

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>