arm64: dts: mt6358: Add the compatible for the regulators

The regulators are expected to be instantiated with matching the
device-tree compatible, so add the proper compatible name under the
regulators node.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
Link: https://lore.kernel.org/r/20200625101757.101775-3-enric.balletbo@collabora.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>