NVMe: Initialize device reference count earlier

commit fb35e914

 upstream.

If an NVMe device becomes ready but fails to create IO queues, the driver
creates a character device handle so the device can be managed. The
device reference count needs to be initialized before creating the
character device.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>