clk: qcom: gcc-sc8280xp: Add runtime PM

The GCC block on SC8280XP is powered by the CX rail. We need to ensure
that it's enabled to prevent unwanted power collapse.

Enable runtime PM to keep the power flowing only when necessary.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230619-topic-sc8280xp-clk-rpm-v1-2-1e5e1064cdb2@linaro.org


Signed-off-by: Bjorn Andersson <andersson@kernel.org>