vdpa/mlx5: fix mkey creation check

The return value of "mlx5_os_wrapped_mkey_create" is checked in the
caller. A zero means success without any error.

The typo in the if-condition should be fixed in case there is a
misjudgment.

Fixes: 398ea8450c ("vdpa/mlx5: workaround dirty bitmap MR creation")
Cc: stable@dpdk.org

Signed-off-by: Bing Zhao <bingz@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>

drivers/vdpa/mlx5/mlx5_vdpa_lm.c

@@ -47,7 +47,7 @@ mlx5_vdpa_dirty_bitmap_set(struct mlx5_vdpa_priv *priv, uint64_t log_base,
 					      (void *)(uintptr_t)log_base,
 					      log_size, &priv->lm_mr);
 
-	if (!ret) {
+	if (ret) {
 		DRV_LOG(ERR, "Failed to allocate wrapped MR for lm.");
 		return -1;
 	}