dt-bindings: regulator: Document MediaTek MT6316 PMIC Regulators

dt-bindings: regulator: Document MediaTek MT6316 PMIC Regulators

Add bindings for the regulators found in the MediaTek MT6316 PMIC,
usually found in board designs using the MT6991 Dimensity 9400 and
on MT8196 Kompanio SoC for Chromebooks.

This chip is fully controlled by SPMI and has multiple variants
providing different phase configurations.

Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20251027110527.21002-2-angelogioacchino.delregno@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>