dt-bindings: remoteproc: imx_rproc: support i.MX8ULP

Add i.MX8ULP remote processor(Cortex-M33) compatible string

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20210622060148.18411-2-peng.fan@oss.nxp.com
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Author: MrVan

Documentation/devicetree/bindings/remoteproc/fsl,imx-rproc.yaml

@@ -19,6 +19,7 @@ properties:
       - fsl,imx8mm-cm4
       - fsl,imx8mn-cm7
       - fsl,imx8mp-cm7
+      - fsl,imx8ulp-cm33
       - fsl,imx7d-cm4
       - fsl,imx7ulp-cm4
       - fsl,imx6sx-cm4