dt-bindings: pci: layerscape-pci: Add EP mode compatible strings for ls1028a

Add EP mode compatible string for ls1028a.

Link: https://lore.kernel.org/r/20220311234938.8706-4-leoyang.li@nxp.comSigned-off-by: Xiaowei Bao <xiaowei.bao@nxp.com>
Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/layerscape-pci.txt

@@ -23,6 +23,7 @@ Required properties:
         "fsl,ls1012a-pcie"
         "fsl,ls1028a-pcie"
   EP mode:
+	"fsl,ls1028a-pcie-ep", "fsl,ls-pcie-ep"
 	"fsl,ls1046a-pcie-ep", "fsl,ls-pcie-ep"
 	"fsl,ls1088a-pcie-ep", "fsl,ls-pcie-ep"
 	"fsl,ls2088a-pcie-ep", "fsl,ls-pcie-ep"