[SCSI] Improve error message when offlining a device

The current code prints:

scsi 13:0:4:0: scsi: Device offlined - not ready after error recovery

which is repetitively redundant.  This patch changes that message to:

scsi 6:0:6:0: Device offlined - not ready after error recovery

Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>