dt-bindings: phy: qmp: Add support for QMP phy in IPQ8074

IPQ8074 uses QMP PHY controller that provides support to PCIe and
USB. Adding DT binding information for the same.

Reviewed-by: Vivek Gautam <[e-mail]>
Signed-off-by: Varadarajan Narayanan <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

Documentation/devicetree/bindings/phy/qcom-qmp-phy.txt

···
 
 Required properties:
  - compatible: compatible list, contains:
+	       "qcom,ipq8074-qmp-pcie-phy" for PCIe phy on IPQ8074
 	       "qcom,msm8996-qmp-pcie-phy" for 14nm PCIe phy on msm8996,
 	       "qcom,msm8996-qmp-usb3-phy" for 14nm USB3 phy on msm8996.
 
···
 		 "phy", "common", "cfg".
 		For "qcom,msm8996-qmp-usb3-phy" must contain
 		 "phy", "common".
+		For "qcom,ipq8074-qmp-pcie-phy" must contain:
+		 "phy", "common".
 
  - vdda-phy-supply: Phandle to a regulator supply to PHY core block.
  - vdda-pll-supply: Phandle to 1.8V regulator supply to PHY refclk pll block.
···
 		 "pipe<lane-number>" for pipe clock specific to each lane.
  - clock-output-names: Name of the PHY clock that will be the parent for
 		       the above pipe clock.
+
+	For "qcom,ipq8074-qmp-pcie-phy":
+		- "pcie20_phy0_pipe_clk"	Pipe Clock parent
+			(or)
+		  "pcie20_phy1_pipe_clk"
 
  - resets: a list of phandles and reset controller specifier pairs,
 	   one for each entry in reset-names.