firmware: arm_scmi: Add multiple protocols registration support

firmware: arm_scmi: Add multiple protocols registration support

Add the capability for a SCMI driver to register to the core SCMI stack
with multiple SCMI protocols. In such a case the SCMI driver probe
function will end up being called once for each registered protocol
which have been also found as implemented on the platform.

This is especially useful in testing scenarios.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20231221151129.325749-1-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>