scsi: iscsi: Remove unused list 'connlist_err'

I think the last use of this list was removed by
  commit 23d6fefb ("scsi: iscsi: Fix in-kernel conn failure
handling").

Build tested only.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20240503232309.152320-1-linux@treblig.org


Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>