Use `torch.frombuffer` instead of `np.frombuffer`

[fmassa]

PyTorch recently introduced a torch.frombuffer method pytorch/pytorch#59077
We should use it to simplify our code whenever possible, instead of relying on alternatives like torch.from_numpy(np.frombuffer)).

[lc0]

@datumbox I can take a look at this issue. Code search does not show too many of occurrences of np.frombuffer