dt-bindings: arm: fsl: add Protonic MVT board

Add Protonic MVT imx6dl based board

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Documentation/devicetree/bindings/arm/fsl.yaml

@@ -367,6 +367,7 @@ properties:
               - ply,plybas                # Plymovent BAS board
               - ply,plym2m                # Plymovent M2M board
               - poslab,imx6dl-savageboard # Poslab SavageBoard Dual
+              - prt,prtmvt                # Protonic MVT board
               - prt,prtrvt                # Protonic RVT board
               - prt,prtvt7                # Protonic VT7 board
               - rex,imx6dl-rex-basic      # Rex Basic i.MX6 Dual Lite Board