iio: light: max44009: add missing OF device matching

iio: light: max44009: add missing OF device matching

The driver currently matches only via i2c_device_id, but also has
of_device_id table:

  drivers/iio/light/max44009.c:545:34: error: ‘max44009_of_match’ defined but not used [-Werror=unused-const-variable=]

Fixes: 6aef699a7d7e ("iio: light: add driver for MAX44009")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230312153429.371702-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>