arm64: dts: mediatek: mt7988a-bpi-r4: Add MediaTek MT6682A/RT5190A PMIC

Bananapi R4 Board contains a MT6682A pmic which is compatible to rt5190a.
Add its node to the i2 controller.

The BananaPi R4 board has a MediaTek MT6682A PMIC, a rebrand of the
Richtek RT5190A chip, connected to the I2C0 bus.

Add the relevant node and, while at it, also configure the regulators
from this PMIC that are used on this board.

Only Buck2/Buck3 voltage can be controlled by software.

BUCK4 input is 5V from BUCK1 output, and the resistor (mapped to RP30/RP31
on BPI-R4) configures BUCK4 output to 1.8V.
LDO input is 3.3V from 3.3VD, and the resistor (mapped to RP38/RP40 on
BPI-R4) configures LDO output to 1.8V.

Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20241220163838.114786-2-linux@fw-web.de


Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>