dt-bindings: PCI: fsl,layerscape-pcie-ep: Drop deprecated windows

dt-bindings: PCI: fsl,layerscape-pcie-ep: Drop deprecated windows

The example DTS uses 'num-ib-windows' and 'num-ob-windows' properties
but these are not defined in the binding.  Binding also does not
reference snps,dw-pcie-common.yaml, probably because it is quite
different even though the device is based on Synopsys controller.

The properties are actually deprecated, so simply drop them from the
example.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250307081327.35153-1-krzysztof.kozlowski@linaro.org