[fx] refactored the file structure of patched function and module (#1238)

* [fx] refactored the file structure of patched function and module

* polish code

colossalai/fx/tracer/meta_patch/patched_module/linear.py

@@ -0,0 +1,9 @@
+import torch
+from ..registry import meta_patched_module
+
+
+@meta_patched_module.register(torch.nn.Linear)
+def torch_nn_linear(self, input):
+    last_dim = input.shape[-1]
+    assert last_dim == self.in_features, f'Expected hidden size {self.in_features} but got {last_dim} for the torch.nn.Linear patch'
+    return torch.empty(input.shape[:-1] + (self.out_features,), device="meta")