graphics/lvgl: Upgrade LVGL to v9.4.0

- Update CMakeLists.txt to use LVGL v9.4.0
- Update Kconfig with new v9.4.0 configuration options
- Update Makefile with new LVGL version
- Includes support for new drawing backends (G2D, DMA2D, OPENGLES, PPA, EVE)
- Includes new NuttX-specific features (mouse support, independent image heap)
- Update documentation strings and configuration hierarchy

Signed-off-by: rongyichang <[email protected]>

Author: terry0012

graphics/lvgl/CMakeLists.txt

@@ -31,7 +31,7 @@ if(CONFIG_GRAPHICS_LVGL)
     FetchContent_Declare(
       lvgl_fetch
       DOWNLOAD_DIR ${CMAKE_CURRENT_LIST_DIR}
-      URL "https://github.com/lvgl/lvgl/archive/refs/tags/v9.2.1.zip" SOURCE_DIR
+      URL "https://github.com/lvgl/lvgl/archive/refs/tags/v9.4.0.zip" SOURCE_DIR
           ${CMAKE_CURRENT_LIST_DIR}/lvgl BINARY_DIR
           ${CMAKE_BINARY_DIR}/apps/graphics/lvgl/lvgl
       DOWNLOAD_NO_PROGRESS true