RDMA/rxe: Update wqe_index for each wqe error completion

RDMA/rxe: Update wqe_index for each wqe error completion

Previously, if user space keeps sending abnormal wqe, queue.index will
keep increasing while qp->req.wqe_index doesn't. Once
qp->req.wqe_index==queue.index in next round, req_next_wqe() will treat
queue as empty. In such case, no new completion would be generated.

Update wqe_index for each wqe completion so that req_next_wqe() can get
next wqe properly.

Link: https://lore.kernel.org/r/1658307368-1851-2-git-send-email-lizhijian@fujitsu.com
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>