[SCSI] fix incorrect value of SCSI_MAX_SG_CHAIN_SEGMENTS due to include file ordering

If the compiled object doesn't include linux/scatterlist.h before
scsi/scsi.h, it will get an incorrect definition of
SCSI_MAX_SG_CHAIN_SEGMENTS.

Signed-off-by: David Dillow <dillowda@ornl.gov>
Cc: stable@kernel.org
Signed-off-by: James Bottomley <James.Bottomley@suse.de>