nvme: fix bug with PCI IRQ pins on teardown

nvme: fix bug with PCI IRQ pins on teardown

When the submission and completion queues are being torn down
the IRQ will be asserted for the completion queue when the
submsission queue is deleted. Then when the completion queue
is deleted it stays asserted. Thus, on systems that do
not use MSI, no further interrupts can be triggered on the host.

Linux sees this as a long delay when unbinding the nvme device.
Eventually the interrupt timeout occurs and it continues.

To fix this we ensure we deassert the IRQ for a CQ when it is
deleted.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>