arm64: dts: meson-axg: add GE2D node

This adds the node for the GE2D accelerator unit.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20201202174417.3778306-5-narmstrong@baylibre.com