[SCSI] correct some dropped const compiler warnings

Make the vendor, model and rev fields in scsi_device pointers to const
and update a few prototypes of functions using them.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
index e69477d..f01ec0a 100644
--- a/drivers/scsi/scsi_devinfo.c
+++ b/drivers/scsi/scsi_devinfo.c
@@ -354,8 +354,9 @@
  *     @model, if found, return the matching flags value, else return
  *     the host or global default settings.
  **/
-int scsi_get_device_flags(struct scsi_device *sdev, unsigned char *vendor,
-			  unsigned char *model)
+int scsi_get_device_flags(struct scsi_device *sdev,
+			  const unsigned char *vendor,
+			  const unsigned char *model)
 {
 	struct scsi_dev_info_list *devinfo;
 	unsigned int bflags;