net/mlx5: Check returned value from health recover sequence

MLX5_INTERFACE_STATE_UP is far from being reliable check for success to
recover, because it can be changed any time and health logic doesn't
have any locks to protect from it.

The locks are not needed here because health recover is good to have,
but not must to success, so rely on the returned value from the
mlx5_recover_device() as a marker for success/failure.

Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>