dt-bindings: PCI: sifive,fu740-pcie: Fix include placement in DTS example

dt-bindings: PCI: sifive,fu740-pcie: Fix include placement in DTS example

Coding style and common logic dictates that headers should not be
included in device nodes.  No functional impact.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20250324125202.81986-2-krzysztof.kozlowski@linaro.org