dt-bindings: iio: dac: AD5770R: update maintainers

Update bindings maintainerns section.

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Acked-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20220526134603.75216-5-alexandru.tachici@analog.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>