dt-bindings: mxsfb: Add compatible for i.MX8MN

NXP's i.MX8MN has an LCDIF as well.
Signed-off-by: NMarek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Link: https://lore.kernel.org/r/20210620225028.189637-1-marex@denx.deSigned-off-by: NRob Herring <robh@kernel.org>

Documentation/devicetree/bindings/display/fsl,lcdif.yaml

@@ -27,6 +27,7 @@ properties:
               - fsl,imx6ul-lcdif
               - fsl,imx7d-lcdif
               - fsl,imx8mm-lcdif
+              - fsl,imx8mn-lcdif
               - fsl,imx8mq-lcdif
           - const: fsl,imx6sx-lcdif