arm64: dts: allwinner: h6: tanix-tx6: Add I2C node

Tanix TX6 has a LED display driven by FD650.

Currently there is no Linux driver nor any binding for it. However, we
can at least provide I2C node in DT, so user space scripts or programs
can manually control it.

Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20211121115002.693329-1-jernej.skrabec@gmail.com