regulator: max8973: Finalize switch to GPIO descriptors

regulator: max8973: Finalize switch to GPIO descriptors

The dvs gpio was still using a legacy number passed from the
platform data. There are no in-tree users of the platform data
so just switch it to a gpio descriptor and obtain it in probe(),
the device tree users will work just as fine with this.

Drop the entirely unused enable_gpio from the platform data
as well. The device tree bindings mentions this but the driver
does not look for it and makes no use of it: it should probably
be implemented properly in a separate patch.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://msgid.link/r/20240220-descriptors-regulators-v1-1-097f608694be@linaro.org
Acked-by: Lee Jones <lee@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>