RDMA/rxe: Remove mc_grp_pool from struct rxe_dev

Remove struct rxe_dev mc_grp_pool field. This field is no longer used.

Link: https://lore.kernel.org/r/20220407184849.14359-1-rpearsonhpe@gmail.comSigned-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/sw/rxe/rxe_verbs.h

@@ -394,7 +394,6 @@ struct rxe_dev {
 	struct rxe_pool		cq_pool;
 	struct rxe_pool		mr_pool;
 	struct rxe_pool		mw_pool;
-	struct rxe_pool		mc_grp_pool;
 
 	/* multicast support */
 	spinlock_t		mcg_lock;