Fix attempt to create a tensor with dtype "target" (#330)

* Fix attempt to create a tensor with dtype "target"

* Check if dequant_dtype is None before string comparison with target

Author: blepping

ops.py

@@ -153,7 +153,7 @@ def ggml_save_to_state_dict(self, destination, prefix, keep_vars):
         # Take into account space required for dequantizing the largest tensor
         if self.largest_layer:
             shape = getattr(self.weight, "tensor_shape", self.weight.shape)
-            dtype = self.dequant_dtype or torch.float16
+            dtype = (self.dequant_dtype and self.dequant_dtype != "target") or torch.float16
             temp = torch.empty(*shape, device=torch.device("meta"), dtype=dtype)
             destination[prefix + "temp.weight"] = temp