scsi: rename SCSI_MAX_{SG, SG_CHAIN}_SEGMENTS

Rename SCSI_MAX_SG_SEGMENTS to SG_CHUNK_SIZE, which means the amount
we fit into a single scatterlist chunk.

Rename SCSI_MAX_SG_CHAIN_SEGMENTS to SG_MAX_SEGMENTS.

Will move these 2 generic definitions to scatterlist.h later.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Bart Van Assche <bart.vanassche@sandisk.com> (for ib_srp changes)
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/ata/pata_icside.c

@@ -294,7 +294,7 @@ static int icside_dma_init(struct pata_icside_info *info)
 
 static struct scsi_host_template pata_icside_sht = {
 	ATA_BASE_SHT(DRV_NAME),
-	.sg_tablesize		= SCSI_MAX_SG_CHAIN_SEGMENTS,
+	.sg_tablesize		= SG_MAX_SEGMENTS,
 	.dma_boundary		= IOMD_DMA_BOUNDARY,
 };