dibs: Register smc as dibs_client

dibs: Register smc as dibs_client

Formally register smc as dibs client. Functionality will be moved by
follow-on patches from ism_client to dibs_client until eventually
ism_client can be removed.
As DIBS is only a shim layer without any dependencies, we can depend SMC
on DIBS without adding indirect dependencies. A follow-on patch will
remove dependency of SMC on ISM.

Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Julian Ruess <julianr@linux.ibm.com>
Link: https://patch.msgid.link/20250918110500.1731261-5-wintera@linux.ibm.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>