regulator: Add driver for MT6331 PMIC regulators

Add a driver for the regulators found in the MT6331 PMIC.
This PMIC features six buck and 21 Low DropOut (LDO) regulators.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220913123456.384513-3-angelogioacchino.delregno@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: AngeloGioacchino Del Regno

drivers/regulator/Kconfig

@@ -787,6 +787,15 @@ config REGULATOR_MT6323
 	  This driver supports the control of different power rails of device
 	  through regulator interface.
 
+config REGULATOR_MT6331
+	tristate "MediaTek MT6331 PMIC"
+	depends on MFD_MT6397
+	help
+	  Say y here to select this option to enable the power regulator of
+	  MediaTek MT6331 PMIC.
+	  This driver supports the control of different power rails of device
+	  through regulator interface
+
 config REGULATOR_MT6358
 	tristate "MediaTek MT6358 PMIC"
 	depends on MFD_MT6397

drivers/regulator/Makefile

@@ -95,6 +95,7 @@ obj-$(CONFIG_REGULATOR_MPQ7920) += mpq7920.o
 obj-$(CONFIG_REGULATOR_MT6311) += mt6311-regulator.o
 obj-$(CONFIG_REGULATOR_MT6315) += mt6315-regulator.o
 obj-$(CONFIG_REGULATOR_MT6323)	+= mt6323-regulator.o
+obj-$(CONFIG_REGULATOR_MT6331)	+= mt6331-regulator.o
 obj-$(CONFIG_REGULATOR_MT6358)	+= mt6358-regulator.o
 obj-$(CONFIG_REGULATOR_MT6359)	+= mt6359-regulator.o
 obj-$(CONFIG_REGULATOR_MT6360) += mt6360-regulator.o