Revert "【KernelGen】Add einsum operator (#1731)" (#3035)

This reverts commit e23da3c.

Author: factnn

benchmark/test_einsum.py

@@ -195,7 +195,6 @@ def torch_ge(v):
     ("divide_.Tensor", true_divide_),
     ("divide_.Tensor_mode", div_mode_),
     ("dot", dot),
-    ("einsum", einsum),
     ("elu", elu),
     ("elu_", elu_),
     ("elu_backward", elu_backward),

src/flag_gems/__init__.py

@@ -109,7 +109,6 @@
 )
 from flag_gems.ops.dot import dot
 from flag_gems.ops.dropout import dropout, dropout_backward
-from flag_gems.ops.einsum import einsum
 from flag_gems.ops.elu import elu, elu_, elu_backward
 from flag_gems.ops.embedding import embedding, embedding_backward
 from flag_gems.ops.embedding_dense_backward import embedding_dense_backward
@@ -490,7 +489,6 @@
     "dot",
     "dropout",
     "dropout_backward",
-    "einsum",
     "elu",
     "elu_",
     "elu_backward",