dt-bindings: phy: qcom,snps-eusb2: document the SM8650 Synopsys eUSB2 PHY

Document the Synopsys eUSB2 PHY on the SM8650 Platform by using
the SM8550 as fallback.

Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Neil Armstrong <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

Documentation/devicetree/bindings/phy/qcom,snps-eusb2-phy.yaml

···
       - items:
           - enum:
               - qcom,sdx75-snps-eusb2-phy
+              - qcom,sm8650-snps-eusb2-phy
           - const: qcom,sm8550-snps-eusb2-phy
       - const: qcom,sm8550-snps-eusb2-phy