firmware: arm_scmi: Add SCMI v3.1 clock notifications

Add SCMI v3.1 clock pre and post notifications.

Link: https://lore.kernel.org/r/20220330150551.2573938-20-cristian.marussi@arm.com


Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>