RDMA/hns: Remove unused CMDQ member

The hcr_mutex was used to serialize mailbox post. Now that mailbox
supports concurrency, this variable is no longer useful.

Fixes: a389d01 ("RDMA/hns: Enable all CMDQ context")
Link: https://lore.kernel.org/r/1621482876-35780-4-git-send-email-liweihang@huawei.com
Signed-off-by: Lang Cheng <chenglang@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/hns/hns_roce_device.h

@@ -555,7 +555,6 @@ struct hns_roce_cmd_context {
 
 struct hns_roce_cmdq {
 	struct dma_pool		*pool;
-	struct mutex		hcr_mutex;
 	struct semaphore	poll_sem;
 	/*
 	 * Event mode: cmd register mutex protection,