vdev_id: Fix enclosure_symlinks feature
The vdev_id.conf "enclosure_symlinks" option persistently creates
and maps /dev/by-enclosure symlinks to dynamic /dev/sg* devices.
This patch fixes two issues:
- The enclosure_symlinks feature was accidentally broken in: vdev_id: Support daisy-chained JBODs in multipath mode
- Even when working, the feature numbered the enclosure sequentially rather than by HBA port number. That meant that if a port was down or didn't appear in sysfs, then the enclosure_sumlinks numbers would be numbered wrong.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #12660