iio: adc: max1027: Simplify the _set_trigger_state() helper

The call to max1027_enable_trigger() is the same in both cases thanks to
the 'state' variable, so factorize a little bit to simplify the code and
explain why we call this helper.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20210921115408.66711-8-miquel.raynal@bootlin.com


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