arm64: dts: mediatek: mt8173-elm: Remove regulators from thermal node

arm64: dts: mediatek: mt8173-elm: Remove regulators from thermal node

The only reason to have a regulator in the thermal node is to keep
the CPU cores up while reading temperatures, but this is incorrect
because the AUXADC Thermal IP doesn't need any regulators to work,
at all.

Since the thermal node was inherited only for adding vregs, remove
it entirely.
This change is safe also because, among other things, the actual
driver never used those regulators anyway.

This also fixes a dtbs_check warning.

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