The MPFS system controller run_service() helper only submits the mailbox request but does not read back the response data. However, the caller must explicitly receive the response. Add a public system controller helper to receive mailbox service responses to populate the response buffer after issuing a system controller request. Without this, the drivers copy uninitialised stack data instead of mailbox response data, resulting in deterministic output. Signed-off-by: Jamie Gibbons <jamie.gibbons@microchip.com> Acked-by: Conor Dooley <conor.dooley@microchip.com>