arm64: dts: mt8183-kukui: clean up regulator tree

arm64: dts: mt8183-kukui: clean up regulator tree

Some regulators in the kukui device tree are modeled incorrectly. Some
are missing supplies and some switches are incorrectly modeled as
voltage regulators. A pass-through was incorrectly modeled as a
regulator.

Add supplies where missing, remove voltage constraints for "switches",
and drop the "bl_pp5000" pass-through.

This depends on commit 2a99858c172e ("arm64: dts: mediatek: mt8183-kukui:
Add PMIC regulator supplies") for reg_vsys.

Fixes: cd894e274b74 ("arm64: dts: mt8183: Add krane-sku176 board")
Fixes: f15722c0fef0 ("arm64: dts: mt8183: Add pwm and backlight node")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20240625095441.3474194-1-wenst@chromium.org
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>