[SCSI] st: fix test of value range in st_set_options()

value cannot logically be less than START and greater than BUFFERSIZE.

#define EXTENDED_SENSE_START  18

// vi include/scsi/scsi_cmnd.h +105
#define SCSI_SENSE_BUFFERSIZE 	96

[akpm@linux-foundation.org: fix warning]
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>