IB/hfi1: Remove unreachable code

Remove unreachable code from RC ack handling to fix an
smatch error.

Fixes: 633d273995 ("staging/rdma/hfi1: use mod_timer when appropriate")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/staging/rdma/hfi1/rc.c

@@ -1497,7 +1497,7 @@ reserved:
 		/* Ignore reserved NAK codes. */
 		goto bail_stop;
 	}
-	return ret;
+	/* cannot be reached  */
 bail_stop:
 	hfi1_stop_rc_timers(qp);
 	return ret;