ARM: dts: sun4i: inet9f-rev03: Add support for game buttons / joysticks

The inet9f-rev03 tablet has multiple fire-buttons / direction controls,
add support for these using the same axis mapping as ps2 compatible game
controllers with the same stick / button layout use.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>