mlx4: remove leftover idr_pre_get() call

Commit 6a9200603d76 ("IB/mlx4: convert to idr_alloc()") forgot to remove
idr_pre_get() call in mlx4_ib_cm_paravirt_init().  It's unnecessary and
idr_pre_get() will soon be deprecated.  Remove it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jack Morgenstein <jackm@dev.mellanox.co.il>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/infiniband/hw/mlx4/cm.c

@@ -362,7 +362,6 @@ void mlx4_ib_cm_paravirt_init(struct mlx4_ib_dev *dev)
 	INIT_LIST_HEAD(&dev->sriov.cm_list);
 	dev->sriov.sl_id_map = RB_ROOT;
 	idr_init(&dev->sriov.pv_id_table);
-	idr_pre_get(&dev->sriov.pv_id_table, GFP_KERNEL);
 }
 
 /* slave = -1 ==> all slaves */