iio: adc: max1027: Rename a helper

Make it clear that the *_set_trigger_state() hook is responsible for
cnvst based conversions by renaming the helper. This may avoid
confusions with software trigger support that is going to be
introduced.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20210921115408.66711-6-miquel.raynal@bootlin.com


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