IB/mlx5: Remove dead code

The value of the local variable index is never used in reg_mr_callback().
Signed-off-by: Eli Cohen <eli@mellanox.com>

[ Remove now-unused variable delta too.  - Roland ]
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/mlx5/mr.c

@@ -72,14 +72,8 @@ static void reg_mr_callback(int status, void *context)
 	int c = order2idx(dev, mr->order);
 	struct mlx5_cache_ent *ent = &cache->ent[c];
 	u8 key;
-	unsigned long delta = jiffies - mr->start;
-	unsigned long index;
 	unsigned long flags;
 
-	index = find_last_bit(&delta, 8 * sizeof(delta));
-	if (index == 64)
-		index = 0;
-
 	spin_lock_irqsave(&ent->lock, flags);
 	ent->pending--;
 	spin_unlock_irqrestore(&ent->lock, flags);