Migrate gen_oplist.py to use executorch/codegen instead of pytorch torchgen (#11104)

Summary:
Pull Request resolved: #11104

As titled, after #10939 we are able to use `executorch.codegen` APIs instead of `torchgen.executorch` APIs. This PR moves `gen_oplist.py` to use the new `executorch.codgen` API.

Reviewed By: kirklandsign

Differential Revision: D75307480

Author: larryliu0820

codegen/tools/gen_oplist.py

@@ -12,7 +12,7 @@
 from typing import Any, Dict, List, Optional, Set
 
 import yaml
-from torchgen.executorch.parse import strip_et_fields
+from executorch.codegen.parse import strip_et_fields
 
 from torchgen.gen import LineLoader, parse_native_yaml_struct
 from torchgen.selective_build.operator import SelectiveBuildOperator

codegen/tools/targets.bzl

@@ -15,8 +15,9 @@ def define_common_targets(is_fbcode = False):
         visibility = [
             "//executorch/...",
         ],
-        external_deps = ["torchgen"],
-        deps = select({
+        deps = [
+            "//executorch/codegen:gen_lib",
+        ] + select({
             "DEFAULT": [],
             "ovr_config//os:linux": [] if runtime.is_oss else ["//executorch/codegen/tools/fb:selective_build"],  # TODO(larryliu0820) :selective_build doesn't build in OSS yet
         }),
@@ -49,7 +50,6 @@ def define_common_targets(is_fbcode = False):
         deps = [
             ":yaml_util",
         ],
-        external_deps = ["torchgen"],
     )
 
     runtime.python_binary(