vdpa/mlx5: Fix clearing of VIRTIO_NET_F_MAC feature bit

stable inclusion
from stable-v5.16
commit ef76eb83
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5WXCZ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ef76eb83a17e803a66b64ac95b36ae48b3d17c22
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Cited patch in the fixes tag clears the features bit during reset.
mlx5 vdpa device feature bits are static decided by device capabilities.
These feature bits (including VIRTIO_NET_F_MAC) are initialized during
device addition time.

Clearing features bit in reset callback cleared the VIRTIO_NET_F_MAC. Due
to this, MAC address provided by the device is not honored.

Fix it by not clearing the static feature bits during reset.

Fixes: 0686082d ("vdpa: Add reset callback in vdpa_config_ops")
Signed-off-by: NParav Pandit <parav@nvidia.com>
Reviewed-by: NEli Cohen <elic@nvidia.com>
Link: https://lore.kernel.org/r/20211026175519.87795-7-parav@nvidia.comSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NPengyuan Zhao <zhaopengyuan@hisilicon.com>

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -1811,7 +1811,6 @@ static int mlx5_vdpa_reset(struct vdpa_device *vdev)
 	clear_vqs_ready(ndev);
 	mlx5_vdpa_destroy_mr(&ndev->mvdev);
 	ndev->mvdev.status = 0;
-	ndev->mvdev.mlx_features = 0;
 	++mvdev->generation;
 	return 0;
 }