The CNTLID value is required to be unique, and we do rely on this
for correct operation. So reject any controller for which a non-unique
CNTLID has been detected.

Based on a patch from Hannes Reinecke.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>