firmware: arm_scmi: Add clock OEM config clock operations

firmware: arm_scmi: Add clock OEM config clock operations

Expose a couple of new SCMI clock operations to get and set OEM specific
clock configurations when talking to an SCMI v3.2 compliant.

Issuing such requests against an SCMI platform server not supporting v3.2
extension for OEM specific clock configurations will fail.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20230826125308.462328-7-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>