clk: qcom: cpu-8996: simplify the cpu_clk_notifier_cb

- Do not use the Alt PLL completely. Switch to smux when necessary to
  prevent overvolting
- Restore the parent in case the rate change aborts for some reason
- Do not duplicate resetting the parent in set_parent operation.

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/20230113120544.59320-8-dmitry.baryshkov@linaro.org