RDMA/hns: Fix ah error counter in sw stat not increasing

RDMA/hns: Fix ah error counter in sw stat not increasing

There are several error cases where hns_roce_create_ah() returns
directly without jumping to sw stat path, thus leading to a problem
that the ah error counter does not increase.

Fixes: ee20cc17e9d8 ("RDMA/hns: Support DSCP")
Fixes: eb7854d63db5 ("RDMA/hns: Support SW stats with debugfs")
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://patch.msgid.link/20240912115700.2016443-1-huangjunxian6@hisilicon.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>