Fix lp layernorm weight (#2954)

* lp layernorm weight fix

* Update composer/algorithms/low_precision_layernorm/low_precision_layernorm.py

Co-authored-by: Mihir Patel <mihir.v.patel7@gmail.com>

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Co-authored-by: Brian <23239305+b-chu@users.noreply.github.com>
Co-authored-by: Mihir Patel <mihir.v.patel7@gmail.com>

composer/algorithms/low_precision_layernorm/low_precision_layernorm.py

@@ -143,7 +143,7 @@ def _to_LPLayerNorm(layer: torch.nn.Module, module_index: int) -> LPLayerNorm:
     lp_layernorm = LPLayerNorm(layer.normalized_shape, layer.eps, layer.elementwise_affine)
 
     with torch.no_grad():
-        if hasattr(layer, 'weight'):
+        if layer.weight is None:  # pyright: ignore[reportUnnecessaryComparison]
             lp_layernorm.register_parameter('weight', None)
         else:
             lp_layernorm.weight.copy_(layer.weight)  # type: ignore