blk-mq: fix kabi broken in struct bio

hulk inclusion
category: bugfix
bugzilla: 187921, https://gitee.com/openeuler/kernel/issues/I66VDB


CVE: NA

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Enable CONFIG_BLK_CGROUP_IOCOST will cause kabi broken, use reserved
fields to fix it.

Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>