Fix LinearInt8 recursive quantization (#791)

Test plan:
```
% python3 torchchat.py generate llama2 --dtype float16 --quantize '{"linear:int8": {"groupsize": 0}}' --prompt "Once upon a time," --device mps
Using device=mps 
Loading model...
Time to load model: 29.03 seconds
Quantizing the model with: {'linear:int8': {'groupsize': 0}}
Time to quantize model: 14.37 seconds
```

Fixes #788

Author: malfet

quantize.py

@@ -410,8 +410,8 @@ def quantize(self, module):
                             groupsize=self.groupsize,
                         ),
                     )
-                else:
-                    self.quantize(child)
+            else:
+                self.quantize(child)
 
         return module