dt-bindings: clock: qcom,msm8996-apcc: add sys_apcs_aux clock

The MSM8996 CPU clock controller can make use of the sys_apcs_aux clock.
Add it to the bindings.

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230113120544.59320-2-dmitry.baryshkov@linaro.org