arm64: dts: meson-sm1-sei610: add HDMI display support

Add the HDMI support nodes for the Amlogic SM1 Based SEI610 Board.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>