hw/input/stellaris_gamepad: Free StellarisGamepad::keycodes[] array

hw/input/stellaris_gamepad: Free StellarisGamepad::keycodes[] array

Commit 0be6bfac62 ("qdev: Implement variable length array properties")
added the DEFINE_PROP_ARRAY() macro with the following comment:

  * It is the responsibility of the device deinit code to free the
  * @_arrayfield memory.

Commit a75f336b97 added:

  DEFINE_PROP_ARRAY("keycodes", StellarisGamepad, num_buttons,
                    keycodes, qdev_prop_uint32, uint32_t),

but forgot to free the 'keycodes' array. Do it in the instance_finalize
handler.

Fixes: a75f336b97 ("hw/input/stellaris_input: Convert to qdev")
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20231121174051.63038-7-philmd@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>