Make SCMI mailbox transport a standalone driver that can be optionally
loaded as a module; while at it, create a dedicated subdirectory and
submenu for SCMI Transports.
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Message-Id: <20240812173340.3912830-6-cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>