dt-bindings: clock: Drop maxim,max77686.txt

The clock binding for Maxim MAX77686/MAX77802/MAX77620 is already
covered by mfd/maxim,max77686.yaml.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250505161943.1433081-1-robh@kernel.org


Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>