nvme-pci: Unblock reset_work on IO failure

mainline inclusion
from mainline-5.2-rc2
commit 2036f726
category: bugfix
bugzilla: 167363
CVE: NA

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

The reset_work waits for queued IO to complete before setting the
controller to live. If any of these times out and requeues, we won't be
able to restart the controller because the reset_work is already running.

Flush all entered requests to a failed completion if a timeout occurs
in the connecting state, and ensure the controller can't transition to
the live state after we've unblocked it from waiting for completions.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <keith.busch@intel.com>

Conflicts:
	drivers/nvme/host/pci.c
	[ Cleanup patch 3b7dffb9("nvme-pci: mark expected switch
	  fall-through") 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>