dt-bindings: PCI: mediatek: Add Airoha EN7532 support

Add a binding for Airoha EN7532, an ARM-based platform SoC integrating the
same PCIe IP as MT7622.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: John Crispin <[email protected]>
Signed-off-by: Felix Fietkau <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Acked-by: Rob Herring <[email protected]>

Author: blogic

Documentation/devicetree/bindings/pci/mediatek-pcie.txt

@@ -7,6 +7,7 @@ Required properties:
 	"mediatek,mt7622-pcie"
 	"mediatek,mt7623-pcie"
 	"mediatek,mt7629-pcie"
+	"airoha,en7523-pcie"
 - device_type: Must be "pci"
 - reg: Base addresses and lengths of the root ports.
 - reg-names: Names of the above areas to use during resource lookup.