ARM: dts: sun7i: lamobo-r1: Remove usb1 vbus regulator

USB1 VBUS is directly tied to the 5V rail on the board. It is not
individually controllable. Drop the regulator.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>