blk-mq: Some tag allocation code refactoring

mainline inclusion
from mainline-v5.14-rc1
commit 56b68085
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I597XM
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=56b68085e536eff2676108f2f8356889a7dbbf55



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The tag allocation code to alloc the sbitmap pairs is common for regular
bitmaps tags and shared sbitmap, so refactor into a common function.

Also remove superfluous "flags" argument from blk_mq_init_shared_sbitmap().

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/1620907258-30910-2-git-send-email-john.garry@huawei.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>
conflict:
	block/blk-mq.c
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>