msi-parent is standard property. Needn't ref to phandle. Add maxItems: 1
for it.

Fix below warning:
  arch/arm64/boot/dts/freescale/fsl-ls1088a-ten64.dtb: fsl-mc@80c000000: msi-parent:0: [16, 0] is too long
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20241007153047.807723-1-Frank.Li@nxp.comSigned-off-by: Rob Herring (Arm) <robh@kernel.org>