The kfree was called to free cqb, while it should free *cqb.

Fixes: 1cbe6fc8 ("IB/mlx5: Add support for CQE compressing")
Signed-off-by: NBodong Wang <bodong@mellanox.com>
Signed-off-by: NLeon Romanovsky <leon@kernel.org>
Signed-off-by: NDoug Ledford <dledford@redhat.com>