[Hexagon] Delete offload runtime, move files to right places (#11090)

Within src/runtime/hexagon
- delete directory android,
- move files from hexagon to ., delete hexagon,
- merge host/hexagon_module.cc with hexagon_module.cc, delete host.

Rename HexagonHostModuleNode to HexagonModuleNode.

CMakeLists.txt

@@ -320,17 +320,7 @@ tvm_file_glob(GLOB RUNTIME_SRCS
 )
 
 if(BUILD_FOR_HEXAGON)
-  # Add file implementing posix_memalign when building the runtime as
-  # a shared library.
-  # This function is actually defined in the static libc, but when linking
-  # a shared library, libc is not linked into it. Some runtime systems
-  # don't implement posix_runtime, which causes runtime failires.
-  # To avoid this issue, Hexagon runtime contains an implementation of
-  # posix_memalign, but it should only be used with the dynamic TVM
-  # runtime, since it would cause multiple definition errors with the
-  # static one.
   if(NOT BUILD_STATIC_RUNTIME)
-    list(APPEND RUNTIME_SRCS src/runtime/hexagon/android/hexagon_posix.cc)
     # Allow undefined symbols (there will be some from libc).
     set(TVM_NO_UNDEFINED_SYMBOLS "")
   endif()

cmake/modules/Hexagon.cmake

@@ -84,9 +84,9 @@ if(NOT USE_HEXAGON)
   if(BUILD_FOR_HOST)
     list(APPEND COMPILER_SRCS src/target/opt/build_hexagon_off.cc)
   endif()
-  list(APPEND RUNTIME_SRCS src/runtime/hexagon/hexagon/hexagon_buffer.cc)
-  list(APPEND RUNTIME_SRCS src/runtime/hexagon/hexagon/hexagon_common.cc)
-  list(APPEND RUNTIME_SRCS src/runtime/hexagon/hexagon/hexagon_user_dma.cc)
+  list(APPEND RUNTIME_SRCS src/runtime/hexagon/hexagon_buffer.cc)
+  list(APPEND RUNTIME_SRCS src/runtime/hexagon/hexagon_common.cc)
+  list(APPEND RUNTIME_SRCS src/runtime/hexagon/hexagon_user_dma.cc)
   return()
 endif()
 
@@ -122,9 +122,7 @@ endfunction()
 
 # Common sources for TVM runtime with Hexagon support
 file_glob_append(RUNTIME_HEXAGON_SRCS
-  "${TVMRT_SOURCE_DIR}/hexagon/hexagon_module.cc"
-  "${TVMRT_SOURCE_DIR}/hexagon/hexagon/*.cc"
-  "${TVMRT_SOURCE_DIR}/hexagon/host/*.cc"
+  "${TVMRT_SOURCE_DIR}/hexagon/*.cc"
 )