dt-bindings: PCI: convert amlogic,meson-pcie.txt to dt-schema

Convert the Amlogic Meson AXG DWC PCIe SoC controller bindings to
dt-schema.

Link: https://lore.kernel.org/r/20221117-b4-amlogic-bindings-convert-v4-5-34e623dbf789@linaro.org


Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>