dt-bindings: PCI: imx6q-pcie: Fix maxItems of clocks and clock-names

dt-bindings: PCI: imx6q-pcie: Fix maxItems of clocks and clock-names

Commit 1352f58d7c8d ("dt-bindings: PCI: pci-imx6: Add external reference
clock input") that added reference clock to the binding was incomplete.

The constraints for "clocks" and "clock-names" still enforce an incorrect
number of items. Update maxItems for both properties to 6 to match the
actual hardware configuration.

Fixes: 1352f58d7c8d ("dt-bindings: PCI: pci-imx6: Add external reference clock input")
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
[mani: commit log]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260324023036.784466-2-hongxing.zhu@nxp.com