py : fix wrong input type for raw_dtype in ggml to gguf scripts (#8928)

Co-authored-by: farbod <farbod.bjary82@gmail.com>

Author: farbodbj

Diff for: convert_llama_ggml_to_gguf.py

@@ -116,7 +116,7 @@ def load(self, data, offset):
         assert quant is not None, 'Unknown tensor type'
         (blksize, tysize) = quant
         offset += 12
-        self.dtype= dtype
+        self.dtype= gguf.GGMLQuantizationType(dtype)
         self.dims = struct.unpack(f'<{n_dims}I', data[offset:offset + (4 * n_dims)])
         offset += 4 * n_dims
         self.name = bytes(data[offset:offset + name_len])