board: amlogic: vim3: fix phy-names property setup

phy-names was improperly implemented resulting in an inoperable USB-OTG
port.

- phy-names = "usb2-phy0\0\0usb2-phy1\0";
+ phy-names = "usb2-phy0\0usb2-phy1";

Signed-off-by: Artem Lapkin <art@khadas.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>