dt-bindings: PCI: qcom: Add MHI registers for IPQ9574

The MHI registers are present in IPQ5332, IPQ6018, IPQ8074 and IPQ9574
SoCs. Hence, add the MHI registers to the binding to allow these registers
to be defined in devicetree.

Signed-off-by: Varadarajan Narayanan <[email protected]>
[mani: commit message rewording]
Signed-off-by: Manivannan Sadhasivam <[email protected]>
Reviewed-by: Krzysztof Kozlowski <[email protected]>
Link: https://patch.msgid.link/[email protected]

Author: quic-varada

Documentation/devicetree/bindings/pci/qcom,pcie.yaml

@@ -175,14 +175,16 @@ allOf:
       properties:
         reg:
           minItems: 5
-          maxItems: 5
+          maxItems: 6
         reg-names:
+          minItems: 5
           items:
             - const: dbi # DesignWare PCIe registers
             - const: elbi # External local bus interface registers
             - const: atu # ATU address space
             - const: parf # Qualcomm specific registers
             - const: config # PCIe configuration space
+            - const: mhi # MHI registers
 
   - if:
       properties: