RDMA/mlx5: Remove dead check for EAGAIN after alloc_mr_from_cache()

alloc_mr_from_cache() no longer returns EAGAIN, this is just dead code
now.

Fixes: aad719dc ("RDMA/mlx5: Allow MRs to be created in the cache synchronously")
Link: https://lore.kernel.org/r/20200914112653.345244-2-leon@kernel.orgSigned-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/mlx5/mr.c

@@ -1392,10 +1392,8 @@ struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	if (order <= mr_cache_max_order(dev) && use_umr) {
 		mr = alloc_mr_from_cache(pd, umem, virt_addr, length, ncont,
 					 page_shift, order, access_flags);
-		if (PTR_ERR(mr) == -EAGAIN) {
-			mlx5_ib_dbg(dev, "cache empty for order %d\n", order);
+		if (IS_ERR(mr))
 			mr = NULL;
-		}
 	} else if (!MLX5_CAP_GEN(dev->mdev, umr_extended_translation_offset)) {
 		if (access_flags & IB_ACCESS_ON_DEMAND) {
 			err = -EINVAL;