modules: lvgl: Update CMakeLists to v9.3

Add new/moved files introduced in v9.3 into the CMakeLists.
Also for using the system monitor the osal is required to have a method to
measure the CPU idle time so the lvgl_zephyr_osal file needs to be always
added.

Signed-off-by: Fabian Blatz <fabianblatz@gmail.com>