regulator: max77686: Fix shared GPIOs

This reverts commit c89c00e2 "regulator: max77686: Pass descriptor
instead of GPIO number" as it has problems with shared GPIOs similar to
that on s2mps11.

Reported-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>