dt-bindings: leds: qcom-lpg: Document PM6150L compatible

The PM6150L LPG modules are compatible with the PM8150L LPG modules,
document the PM6150L LPG compatible as fallback for the PM8150L LPG.

Signed-off-by: Danila Tikhonov <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

Documentation/devicetree/bindings/leds/leds-qcom-lpg.yaml

···
           - qcom,pmk8550-pwm
       - items:
           - enum:
+              - qcom,pm6150l-lpg
+          - const: qcom,pm8150l-lpg
+      - items:
+          - enum:
               - qcom,pm8550-pwm
           - const: qcom,pm8350c-pwm