clk: qcom: dispcc-sm8250: use runtime PM for the clock controller

On sm8250 dispcc and videocc registers are powered up by the MMCX power
domain. Use runtime PM calls to make sure that required power domain is
powered on while we access clock controller's registers.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210829154757.784699-4-dmitry.baryshkov@linaro.org


Signed-off-by: Stephen Boyd <sboyd@kernel.org>