dt-bindings: panel: Add YAML schemas for the Ronbo RB070D30 panel

The Ronbo RB070D30 panel is a 1024x600 MIPI-DSI panel.

Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/c05b961302ec4a2af32ea6c215ec0749b1a9cff7.1550650810.git-series.maxime.ripard@bootlin.com