Fix device and dtype discrepancy in _choose_qparams_affine (#2210)

Summary: Pull Request resolved: #2210

Differential Revision: D74446877

Author: YIWENX14

torchao/quantization/quant_primitives.py

@@ -948,7 +948,9 @@ def _choose_qparams_affine(
         scale = torch.clamp(scale, min=eps)
     else:
         assert mapping_type == MappingType.ASYMMETRIC.name
-        scale = (max_val_pos - min_val_neg) / float(quant_max - quant_min)
+        scale = (max_val_pos - min_val_neg) / torch.tensor(
+            [float(quant_max - quant_min)], dtype=input.dtype, device=input.device
+        )
         scale = torch.clamp(scale, min=eps)
         if zero_point_domain == ZeroPointDomain.NONE.name:
             zero_point = None