Revert "Fix multiple MKL targets"

This reverts commit bcf317c.

Author: huydhn

CMakeLists.txt

@@ -602,13 +602,6 @@ target_compile_definitions(executorch PUBLIC C10_USING_CUSTOM_GENERATED_MACROS)
 target_compile_options(executorch PUBLIC ${_common_compile_options})
 target_link_options_shared_lib(executorch)
 
-#
-# find pytorch lib here to make it available to all sub-directories, trying to
-# call find_package(Torch) multiple times doesn't work because it brings in MKL
-# which is defined once globally
-#
-find_package(Torch CONFIG REQUIRED)
-
 #
 # portable_ops_lib: A library to register core ATen ops using portable kernels,
 # see kernels/portable/CMakeLists.txt.
@@ -756,7 +749,8 @@ if(EXECUTORCH_BUILD_PYBIND)
     add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/devtools)
   endif()
 
-  # to allow pybind to take at::Tensor as input/output
+  # find pytorch lib, to allow pybind to take at::Tensor as input/output
+  find_package(Torch CONFIG REQUIRED)
   find_library(
     TORCH_PYTHON_LIBRARY torch_python PATHS "${TORCH_INSTALL_PREFIX}/lib"
   )

build/Codegen.cmake

@@ -146,9 +146,7 @@ function(gen_custom_ops_aot_lib)
     ${_out_dir}/CustomOpsNativeFunctions.h "${GEN_KERNEL_SOURCES}"
   )
   # Find `Torch`.
-  if(NOT TARGET torch)
-    find_package(Torch REQUIRED)
-  endif()
+  find_package(Torch REQUIRED)
   # This lib uses ATen lib, so we explicitly enable rtti and exceptions.
   target_compile_options(${GEN_LIB_NAME} PRIVATE -frtti -fexceptions)
   target_compile_definitions(${GEN_LIB_NAME} PRIVATE USE_ATEN_LIB=1)

extension/llm/custom_ops/CMakeLists.txt

@@ -69,9 +69,7 @@ install(TARGETS custom_ops DESTINATION lib)
 
 if(EXECUTORCH_BUILD_KERNELS_CUSTOM_AOT)
   # Add a AOT library
-  if(NOT TARGET torch)
-    find_package(Torch CONFIG REQUIRED)
-  endif()
+  find_package(Torch CONFIG REQUIRED)
   add_library(
     custom_ops_aot_lib SHARED
     ${_custom_ops__srcs}