blk-mq: blk-mq: provide forced completion method

mainline inclusion
from mainline-5.8-rc1
commit 7b11eab0
category: bugfix
bugzilla: 175150
CVE: NA

---------------------------

Drivers may need to bypass error injection for error recovery. Rename
__blk_mq_complete_request() to blk_mq_force_complete_rq() and export
that function so drivers may skip potential fake timeouts after they've
reclaimed lost requests.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Conflicts:
	block/blk-mq.c
	include/linux/blk-mq.h
	[ Non bugfix patch c7bb9ad1("block: get rid of
	  q->softirq_done_fn()") is not applied. ]

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>