Moved tx_initialize_low_level.S to example_build for Cortex-M33/M55/M85 GNU (#452) (#514)

The Cortex-M33, M55, and M85 GNU ports incorrectly include tx_initialize_low_level.S as a library source in CMakeLists.txt. This file is board-specific initialization code that users must
customize for their hardware, and including it in the library causes linker conflicts when users provide their own implementation (e.g., via CMake FetchContent).

This change aligns these ports with the established pattern used by
Cortex-M0/M3/M4/M7 GNU ports:
- Move tx_initialize_low_level.S from src/ to example_build/
- Remove it from CMakeLists.txt target_sources
- Add sample_threadx.c to example_build/ for consistency

Signed-off-by: An Dao <webmaster@taktflow-systems.com>

ports/cortex_m33/gnu/CMakeLists.txt

@@ -1,7 +1,8 @@
-target_sources(${PROJECT_NAME} PRIVATE
+target_sources(${PROJECT_NAME}
+    PRIVATE
+    # {{BEGIN_TARGET_SOURCES}}
     ${CMAKE_CURRENT_LIST_DIR}/src/txe_thread_secure_stack_allocate.c
     ${CMAKE_CURRENT_LIST_DIR}/src/txe_thread_secure_stack_free.c
-    ${CMAKE_CURRENT_LIST_DIR}/src/tx_initialize_low_level.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_context_restore.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_context_save.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_interrupt_control.S
@@ -14,8 +15,10 @@ target_sources(${PROJECT_NAME} PRIVATE
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_stack_build.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_system_return.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_timer_interrupt.S
+    # {{END_TARGET_SOURCES}}
 )
 
-target_include_directories(${PROJECT_NAME} PUBLIC
-    inc
+target_include_directories(${PROJECT_NAME}
+    PUBLIC
+    ${CMAKE_CURRENT_LIST_DIR}/inc
 )

ports/cortex_m55/gnu/CMakeLists.txt

@@ -1,7 +1,8 @@
-target_sources(${PROJECT_NAME} PRIVATE
+target_sources(${PROJECT_NAME}
+    PRIVATE
+    # {{BEGIN_TARGET_SOURCES}}
     ${CMAKE_CURRENT_LIST_DIR}/src/txe_thread_secure_stack_allocate.c
     ${CMAKE_CURRENT_LIST_DIR}/src/txe_thread_secure_stack_free.c
-    ${CMAKE_CURRENT_LIST_DIR}/src/tx_initialize_low_level.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_context_restore.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_context_save.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_interrupt_control.S
@@ -14,8 +15,10 @@ target_sources(${PROJECT_NAME} PRIVATE
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_stack_build.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_system_return.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_timer_interrupt.S
+    # {{END_TARGET_SOURCES}}
 )
 
-target_include_directories(${PROJECT_NAME} PUBLIC
-    inc
+target_include_directories(${PROJECT_NAME}
+    PUBLIC
+    ${CMAKE_CURRENT_LIST_DIR}/inc
 )

ports/cortex_m85/gnu/CMakeLists.txt

@@ -1,7 +1,8 @@
-target_sources(${PROJECT_NAME} PRIVATE
+target_sources(${PROJECT_NAME}
+    PRIVATE
+    # {{BEGIN_TARGET_SOURCES}}
     ${CMAKE_CURRENT_LIST_DIR}/src/txe_thread_secure_stack_allocate.c
     ${CMAKE_CURRENT_LIST_DIR}/src/txe_thread_secure_stack_free.c
-    ${CMAKE_CURRENT_LIST_DIR}/src/tx_initialize_low_level.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_context_restore.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_context_save.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_interrupt_control.S
@@ -14,8 +15,10 @@ target_sources(${PROJECT_NAME} PRIVATE
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_stack_build.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_thread_system_return.S
     ${CMAKE_CURRENT_LIST_DIR}/src/tx_timer_interrupt.S
+    # {{END_TARGET_SOURCES}}
 )
 
-target_include_directories(${PROJECT_NAME} PUBLIC
-    inc
+target_include_directories(${PROJECT_NAME}
+    PUBLIC
+    ${CMAKE_CURRENT_LIST_DIR}/inc
 )