According to Documentation/devicetree/bindings/regulator/regulator.txt
regulator nodes should not be placed under 'simple-bus'.

Mark Rutland also explains about it at:
http://www.spinics.net/lists/linux-usb/msg101497.htmlSigned-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>