[SCSI] fix scsi_device_types overrun in scsi.c

this overrun was spotted by coverity (cid #1403).

If type == ARRAY_SIZE(scsi_device_types), we are off by one.

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>