IB/rdmavt: Add multicast stubs

Adds the function stubs for attach and detach multicast.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/drivers/infiniband/sw/rdmavt/vt.c b/drivers/infiniband/sw/rdmavt/vt.c
index 9b318e9..e69bc8a 100644
--- a/drivers/infiniband/sw/rdmavt/vt.c
+++ b/drivers/infiniband/sw/rdmavt/vt.c
@@ -238,6 +238,10 @@
 	CHECK_DRIVER_OVERRIDE(rdi, destroy_srq);
 	CHECK_DRIVER_OVERRIDE(rdi, query_srq);
 
+	/* Multicast */
+	CHECK_DRIVER_OVERRIDE(rdi, attach_mcast);
+	CHECK_DRIVER_OVERRIDE(rdi, detach_mcast);
+
 	/* Mem Region */
 	CHECK_DRIVER_OVERRIDE(rdi, get_dma_mr);
 	CHECK_DRIVER_OVERRIDE(rdi, reg_user_mr);