phy: sparx5-serdes: power on CMUs individually

Power on the CMU instance, that provides the clock for the serdes, given the
specified serdes mode and index. The CMU instance is looked up, using a
preset map of serdes mode and index to CMU index.

Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
Link: https://lore.kernel.org/r/20230417180335.2787494-6-daniel.machon@microchip.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>