scsi_sysfs: call 'device_add' after attaching device handler

'device_add' will be evaluating the 'is_visible' callback when creating
the sysfs attributes. As by this time the device handler has not been
attached the 'access_state' attribute will never be visible.

This patch moves the code around so that the device handler is present
by the time 'is_visible' is evaluated to correctly display the
'access_state' attribute.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>