qed: Make ll2_cbs static

Fix the following sparse warning:

drivers/net/ethernet/qlogic/qed/qed_ll2.c:2334:20: warning: symbol 'll2_cbs'
was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Acked-by: Michal <Kalderon &lt;michal.kalderon@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>