backlight: ktz8866: Fix module autoloading

Add MODULE_DEVICE_TABLE(), so modules could be properly autoloaded
based on the alias from of_device_id table.

Signed-off-by: Liao Chen <liaochen4@huawei.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Jianhua Lu <lujianhua000@gmail.com>
Link: https://lore.kernel.org/r/20240820121628.42321-1-liaochen4@huawei.com


Signed-off-by: Lee Jones <lee@kernel.org>