scsi: do not display kernel pointer in message logs

It is not good practice to display the kernel pointer in any message logs,
and it doesn't display any additional information. And as we know have
block-layer assigned tags we can use them to differentiate the messages.
So remove any pointer references from the displayed messages.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>