ARM: dts: meson8: add the USB reset line

Now that we support the reset controller on Meson8 we can add the reset
line to the USB PHYs (just like on Meson8b).

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>