dt-bindings: imx6q-pcie: Add i.MX8MM PCIe EP mode compatible string

Add i.MX8MM PCIe endpoint mode compatible string.

Link: https://lore.kernel.org/r/1673847684-31893-2-git-send-email-hongxing.zhu@nxp.comSigned-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml

@@ -24,6 +24,7 @@ properties:
       - fsl,imx8mq-pcie
       - fsl,imx8mm-pcie
       - fsl,imx8mp-pcie
+      - fsl,imx8mm-pcie-ep
 
   reg:
     items: