regulator: add mt6357 regulator

Add regulator driver for the MT6357 PMIC.

Signed-off-by: Fabien Parent <fparent@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
Link: https://lore.kernel.org/r/20221005-mt6357-support-v7-7-477e60126749@baylibre.com


Signed-off-by: Mark Brown <broonie@kernel.org>