firmware: arm_scmi: Add support for debug metrics at the interface

firmware: arm_scmi: Add support for debug metrics at the interface

Since SCMI involves interaction with the entity(software, firmware and/or
hardware) providing services or features, it is quite useful to track
certain metrics(for pure debugging purposes) like how many messages were
sent or received, were there any failures, what kind of failures, ..etc.

Add a new optional config option for the above purpose and the initial
support for counting such key debug metrics.

Signed-off-by: Luke Parkin <luke.parkin@arm.com>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Tested-by: Cristian Marussi <cristian.marussi@arm.com>
Message-Id: <20240805131013.587016-3-sudeep.holla@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>