firmware: arm_scmi: Report frequencies in the perf notifications

Extend the perf notification report to include pre-calculated frequencies
corresponding to the reported limits/levels event; such frequencies are
properly computed based on the stored known OPPs information taking into
consideration if the current operating mode is level indexed or not.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240212123233.1230090-12-cristian.marussi@arm.com


Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>