dt-bindings: pinctrl: document the SM8650 Top Level Mode Multiplexer

Document the Top Level Mode Multiplexer on the SM8650 Platform.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231106-topic-sm8650-upstream-tlmm-v3-1-0e179c368933@linaro.org


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>