dt-bindings: iio: adc: max1238: Fix a typo in the description

Fix a typo in the description, where "interface" is spelled incorrectly.

Signed-off-by: Fabio Estevam <festevam@denx.de>
Link: https://lore.kernel.org/r/20221216004015.2902966-1-festevam@denx.de


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