dt-bindings: PCI: qcom: x1e80100: Make the MHI reg region mandatory

All PCIe controllers found on X1E80100 have MHI register region.
So change the schema to reflect that.

Fixes: 692eadd ("dt-bindings: PCI: qcom: Document the X1E80100 PCIe Controller")
Link: https://lore.kernel.org/linux-pci/20240605-x1e80100-pci-bindings-fix-v2-1-c465e87966fc@linaro.org
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Author: abelvesa

Documentation/devicetree/bindings/pci/qcom,pcie-x1e80100.yaml

@@ -19,11 +19,10 @@ properties:
     const: qcom,pcie-x1e80100
 
   reg:
-    minItems: 5
+    minItems: 6
     maxItems: 6
 
   reg-names:
-    minItems: 5
     items:
       - const: parf # Qualcomm specific registers
       - const: dbi # DesignWare PCIe registers