dt-bindings: dma: qcom: gpi: add compatible for sm8550

The Qualcomm SM8550 uses GPI DMA for its GENI interface. Add a compatible
string for it in the documentation by using the SM6350 as fallback.
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221114-narmstrong-sm8550-upstream-gpi-v1-0-33b28a227c5d@linaro.orgSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/dma/qcom,gpi.yaml

@@ -30,6 +30,7 @@ properties:
               - qcom,sm6375-gpi-dma
               - qcom,sm8350-gpi-dma
               - qcom,sm8450-gpi-dma
+              - qcom,sm8550-gpi-dma
           - const: qcom,sm6350-gpi-dma
       - items:
           - enum: