ide: pass command to ide_map_sg()

* Set IDE_TFLAG_WRITE flag and ->rq also for ATA_CMD_PACKET
  commands.

* Pass command to ->dma_setup method and update all its
  implementations accordingly.

* Pass command instead of request to ide_build_sglist(),
  *_build_dmatable() and ide_map_sg().

While at it:

* Fix scc_dma_setup() documentation + use ATA_DMA_WR define.

* Rename sgiioc4_build_dma_table() to sgiioc4_build_dmatable(),
  change return value type to 'int' and drop unused 'ddir'
  argument.

* Do some minor cleanups in [tx4939]ide_dma_setup().

There should be no functional changes caused by this patch.

Acked-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-floppy.c

@@ -285,9 +285,13 @@ static ide_startstop_t ide_floppy_do_request(ide_drive_t *drive,
 		goto out_end;
 	}
 
+	if (rq_data_dir(rq))
+		cmd->tf_flags |= IDE_TFLAG_WRITE;
+	cmd->rq = rq;
+
 	if (blk_fs_request(rq) || pc->req_xfer) {
 		ide_init_sg_cmd(cmd, rq->nr_sectors);
-		ide_map_sg(drive, rq);
+		ide_map_sg(drive, cmd);
 	}
 
 	pc->sg = hwif->sg_table;