arm64: dts: mediatek: mt8192-asurada: Add MT6315 PMIC supplies

arm64: dts: mediatek: mt8192-asurada: Add MT6315 PMIC supplies

There are two MT6315 PMICs in the MT8192 Asurada design. One has two
outputs ganged together and two outputs unused. The other has three
outputs ganged together, and one left independent.

Add supplies for all the used regulators. In the case of ganged outputs,
add the supply for just the first output.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>