RDMA/hns: Modify congestion abbreviation

driver inclusion
category: cleanup
bugzilla: https://gitee.com/openeuler/kernel/issues/I6N1G4



---------------------------------------------------------------

The currently used abbreviation of cong cannot clearly
indicate the meaning, so the full name congest is used instead.

Signed-off-by: Yixing Liu <liuyixing1@huawei.com>
Reviewed-by: Yangyang Li <liyangyang20@huawei.com>