dt-bindings: PCI: rockchip,rk3399-pcie: Add missing maxItems to ep-gpios

Properties with GPIOs should define number of actual GPIOs, so add
missing maxItems to ep-gpios.  Otherwise multiple GPIOs could be
provided which is not a true hardware description.

Fixes: aa222f9 ("dt-bindings: PCI: Convert Rockchip RK3399 PCIe to DT schema")
Link: https://lore.kernel.org/linux-pci/[email protected]
Signed-off-by: Krzysztof Kozlowski <[email protected]>
Signed-off-by: Krzysztof Wilczyński <[email protected]>
Acked-by: Conor Dooley <[email protected]>

Author: krzk

Documentation/devicetree/bindings/pci/rockchip,rk3399-pcie.yaml

@@ -37,6 +37,7 @@ properties:
     description: This property is needed if using 24MHz OSC for RC's PHY.
 
   ep-gpios:
+    maxItems: 1
     description: pre-reset GPIO
 
   vpcie12v-supply: