The difference of single-core SCP and multi-core SCP device tree is
the presence of child device nodes described SCP cores. The SCP
driver populates the platform device and checks the child nodes
to identify whether it's a single-core SCP or a multi-core SCP.
Add the remoteproc instances of multi-core SCP to the SCP cluster list.
When the SCP driver is removed, it cleanup resources by walking
through the cluster list.
Signed-off-by: Tinghan Shen <tinghan.shen@xxxxxxxxxxxx>