dt-bindings: PCI: fsl,imx6q-pcie: Add Refclk for i.MX95 RC

dt-bindings: PCI: fsl,imx6q-pcie: Add Refclk for i.MX95 RC

Previous Refclk of i.MX95 PCIe RC is on when system boot to kernel. But
boot firmware change the behavior, it is off when boot. So it must be
turned on when it is used. Also it needs be turned off/on for suspend and
resume.

Add one Refclk for i.MX95 PCIe RC. Increase clocks' maxItems to 5 and keep
the same restriction with other compatible string.

Link: https://lore.kernel.org/r/20241126075702.4099164-2-hongxing.zhu@nxp.com
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>