Add torch.float64 as a viable dtype (#379)

Author: eldarkurtic

src/compressed_tensors/quantization/lifecycle/initialize.py

@@ -189,7 +189,7 @@ def _initialize_scale_zero_point(
     else:
         # TODO: consider erroring out in the future as if the dtype if not one of these,
         # there is likely bug
-        if scale_dtype not in [torch.float16, torch.bfloat16, torch.float32]:
+        if scale_dtype not in [torch.float16, torch.bfloat16, torch.float32, torch.float64]:
             scale_dtype = torch.float16
         zp_dtype = quantization_args.pytorch_dtype()