nvme-pci: Don't disable on timeout in reset state

The reset state doesn't dispatch commands that it needs to wait for
anymore. If a timeout occurs in this state, the reset work is already
disabling the controller, so just reset the request's timer.

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