dt-bindings: arm: fsl: add Hummingboard Pulse

Add binding documentation for the SolidRun Hummingboard Pulse board.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Documentation/devicetree/bindings/arm/fsl.yaml

@@ -227,6 +227,7 @@ properties:
               - boundary,imx8mq-nitrogen8m # i.MX8MQ NITROGEN Board
               - fsl,imx8mq-evk            # i.MX8MQ EVK Board
               - purism,librem5-devkit     # Purism Librem5 devkit
+              - solidrun,hummingboard-pulse # SolidRun Hummingboard Pulse
               - technexion,pico-pi-imx8m  # TechNexion PICO-PI-8M evk
           - const: fsl,imx8mq