dt-bindings: Add compatible for BCM2711 DSI1

DSI1 on BCM2711 doesn't require the DMA workaround that is used
on BCM2835/6/7, therefore it needs a new compatible string.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20201203132543.861591-7-maxime@cerno.tech

Documentation/devicetree/bindings/display/brcm,bcm2835-dsi0.yaml

@@ -18,6 +18,7 @@ properties:
 
   compatible:
     enum:
+      - brcm,bcm2711-dsi1
       - brcm,bcm2835-dsi0
       - brcm,bcm2835-dsi1