IB/core: change the return type to void

The function ib_unregister_mad_agent always returns zero. And
this returned value is not checked. As such, chane the return
type to void.

CC: Joe Jin <joe.jin@oracle.com>
CC: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Reviewed-by: Hal Rosenstock <hal@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/mad.c

@@ -605,7 +605,7 @@ static void unregister_mad_snoop(struct ib_mad_snoop_private *mad_snoop_priv)
 /*
  * ib_unregister_mad_agent - Unregisters a client from using MAD services
  */
-int ib_unregister_mad_agent(struct ib_mad_agent *mad_agent)
+void ib_unregister_mad_agent(struct ib_mad_agent *mad_agent)
 {
 	struct ib_mad_agent_private *mad_agent_priv;
 	struct ib_mad_snoop_private *mad_snoop_priv;
@@ -622,7 +622,6 @@ int ib_unregister_mad_agent(struct ib_mad_agent *mad_agent)
 					      agent);
 		unregister_mad_snoop(mad_snoop_priv);
 	}
-	return 0;
 }
 EXPORT_SYMBOL(ib_unregister_mad_agent);
 

include/rdma/ib_mad.h

@@ -673,7 +673,7 @@ struct ib_mad_agent *ib_register_mad_snoop(struct ib_device *device,
  * After invoking this routine, MAD services are no longer usable by the
  * client on the associated QP.
  */
-int ib_unregister_mad_agent(struct ib_mad_agent *mad_agent);
+void ib_unregister_mad_agent(struct ib_mad_agent *mad_agent);
 
 /**
  * ib_post_send_mad - Posts MAD(s) to the send queue of the QP associated