ARM: dts: meson: add the gadget mode properties to the USB0 controller

Testing with a USB RNDIS connection and iperf3 gives the following
results:
- From the host computer to the device at ~250Mbit/s
- From the device to the host computer at ~76Mbit/s

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20200504195105.2909711-1-martin.blumenstingl@googlemail.com