clk: qcom: gcc-qcs404: get rid of the test clock

The test clock isn't in the bindings and apparently it's not used by
anyone upstream.  Remove it.

Suggested-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@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/20221226042154.2666748-9-dmitry.baryshkov@linaro.org