powercap: arm_scmi: Add support for disabling powercaps on a zone

Add support to disable/enable powercapping on a zone.

Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230531152039.2363181-4-cristian.marussi@arm.com


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