CMake: Fix python dependencies in codegen (pytorch#45275)

Summary:
I noticed while working on pytorch#45163 that edits to python files in the  `tools/codegen/api/` directory wouldn't trigger rebuilds. This tells CMake about all of the dependencies, so rebuilds are triggered automatically.

Pull Request resolved: pytorch#45275

Reviewed By: zou3519

Differential Revision: D23922805

Pulled By: ezyang

fbshipit-source-id: 0fbf2b6a9b2346c31b9b0384e5ad5e0eb0f70e9b

Author: peterbell10

cmake/Codegen.cmake

@@ -144,7 +144,7 @@ if(INTERN_BUILD_ATEN_OPS)
   endforeach()
   list(APPEND ATen_CPU_SRCS ${cpu_kernel_cpp})
 
-  file(GLOB all_python "${CMAKE_CURRENT_LIST_DIR}/../tools/codegen/*.py")
+  file(GLOB_RECURSE all_python "${CMAKE_CURRENT_LIST_DIR}/../tools/codegen/*.py")
 
   set(GEN_ROCM_FLAG)
   if(USE_ROCM)