IB/rdmavt: Add multicast functions

This patch adds in the multicast add and remove functions as well as the
ancillary infrastructure needed.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@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 7f56a42..5a094eb 100644
--- a/drivers/infiniband/sw/rdmavt/vt.c
+++ b/drivers/infiniband/sw/rdmavt/vt.c
@@ -305,6 +305,7 @@
 	CHECK_DRIVER_OVERRIDE(rdi, query_srq);
 
 	/* Multicast */
+	rvt_driver_mcast_init(rdi);
 	CHECK_DRIVER_OVERRIDE(rdi, attach_mcast);
 	CHECK_DRIVER_OVERRIDE(rdi, detach_mcast);