dt-bindings: reset: meson-g12a: Add missing USB2 PHY resets

The G12A Documentation lacked these 2 reset lines, but they are present and
used for each USB 2 PHYs.

Add them to the dt-bindings for the upcoming USB support.

Fixes: dbfc5453 ("dt-bindings: reset: meson: add g12a bindings")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>