uboot-imx

dts: rk3399-evb: add regulator-fixed for usb host vbus

rk3399 evb using one gpio to enable 5V output for both USB 2.0
host port, let's use fixed regulator for them.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>