dt-bindings: arm: qcom: Add Lenovo ThinkPad T14s Gen 6

Document the X1E78100-based ThinkPad.

X1E78100 is a binned version of X1E80100, hence use the latter's
compatible string as fallback.

Signed-off-by: Konrad Dybcio <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Bjorn Andersson <[e-mail]>

Documentation/devicetree/bindings/arm/qcom.yaml

···
 
       - items:
           - enum:
+              - lenovo,thinkpad-t14s
+          - const: qcom,x1e78100
+          - const: qcom,x1e80100
+
+      - items:
+          - enum:
               - asus,vivobook-s15
               - lenovo,yoga-slim7x
               - microsoft,romulus13