iio: adc: max1363: add missing adc to max1363_id

max11644-max11647 had an enum value but were not added to the max1363_id,
so they where not selectable in the devictree.

Signed-off-by: Stefan Eichenberger <stefan.eichenberger@netmodule.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>