mpic_init_sys() currently doesn't check whether
subsys_system_register() succeeded or not. Check the return code of
subsys_system_register() and clean up if there's an error.
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
 
 static int mpic_init_sys(void)
 {
+       int rc;
+
        register_syscore_ops(&mpic_syscore_ops);
-       subsys_system_register(&mpic_subsys, NULL);
+       rc = subsys_system_register(&mpic_subsys, NULL);
+       if (rc) {
+               unregister_syscore_ops(&mpic_syscore_ops);
+               pr_err("mpic: Failed to register subsystem!\n");
+               return rc;
+       }
 
        return 0;
 }