dt-bindings: PCI: Make "cdns,max-outbound-regions" optional property

Make "cdns,max-outbound-regions" optional property with the default
being 32.

Link: http://lore.kernel.org/r/20201105165331.GA55814@bogus
Link: https://lore.kernel.org/r/20201106151107.3987-2-kishon@ti.comSigned-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pci/cdns-pcie-ep.yaml

@@ -20,7 +20,4 @@ properties:
     maximum: 32
     default: 32
 
-required:
-  - cdns,max-outbound-regions
-
 additionalProperties: true

Documentation/devicetree/bindings/pci/ti,j721e-pci-ep.yaml

@@ -57,7 +57,6 @@ required:
   - power-domains
   - clocks
   - clock-names
-  - cdns,max-outbound-regions
   - dma-coherent
   - max-functions
   - phys
@@ -86,7 +85,6 @@ examples:
            power-domains = <&k3_pds 239 TI_SCI_PD_EXCLUSIVE>;
            clocks = <&k3_clks 239 1>;
            clock-names = "fck";
-           cdns,max-outbound-regions = <16>;
            max-functions = /bits/ 8 <6>;
            dma-coherent;
            phys = <&serdes0_pcie_link>;