[SCSI] scsi_scan.c: fix compile warnings

drivers/scsi/scsi_scan.c: In function `scsi_probe_and_add_lun':
drivers/scsi/scsi_scan.c:926: warning: unused variable `vend'
drivers/scsi/scsi_scan.c:926: warning: unused variable `mod'
drivers/scsi/scsi_scan.c: At top level:
drivers/scsi/scsi_scan.c:829: warning: `scsi_inq_str' defined but not used

Fix those, tighten up the (somewhat poorly-designed) logging macro and fix
some coding-style warts.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>