sg: remove an unused variable

The 'data_dir' variable is not used in sg_common_write(), hence
remove this variable.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/sg.c

@@ -763,7 +763,7 @@ static int
 sg_common_write(Sg_fd * sfp, Sg_request * srp,
 		unsigned char *cmnd, int timeout, int blocking)
 {
-	int k, data_dir, at_head;
+	int k, at_head;
 	Sg_device *sdp = sfp->parentdp;
 	sg_io_hdr_t *hp = &srp->header;
 
@@ -793,21 +793,6 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp,
 		return -ENODEV;
 	}
 
-	switch (hp->dxfer_direction) {
-	case SG_DXFER_TO_FROM_DEV:
-	case SG_DXFER_FROM_DEV:
-		data_dir = DMA_FROM_DEVICE;
-		break;
-	case SG_DXFER_TO_DEV:
-		data_dir = DMA_TO_DEVICE;
-		break;
-	case SG_DXFER_UNKNOWN:
-		data_dir = DMA_BIDIRECTIONAL;
-		break;
-	default:
-		data_dir = DMA_NONE;
-		break;
-	}
 	hp->duration = jiffies_to_msecs(jiffies);
 	if (hp->interface_id != '\0' &&	/* v3 (or later) interface */
 	    (SG_FLAG_Q_AT_TAIL & hp->flags))