phy: qcom-qmp-combo: drop v4 reference-clock source

phy: qcom-qmp-combo: drop v4 reference-clock source

The source clock for the reference clock should not be described by the
devicetree and instead this relationship should be modelled in the clock
driver.

Drop the management of the source clock from the driver for SC8180X and
SC8280XP. Note that support for the former is not yet in mainline.

Also note that the binding has never been updated to describe the v4
clocks for SC8180X.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20221121085058.31213-4-johan+linaro@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>