ide: fix comment typo in ide.h

Fix typo in the comment to the 'dma_mode' field of the 'struct ide_drive_s'
introduced by the commit 3fccaa192b (ide: add
drive->dma_mode field).

Whilt at it, convert spaces to a tab in the declaration of the neighbouring
'dn' field...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/ide.h

@@ -516,8 +516,8 @@ struct ide_drive_s {
         u8	current_speed;	/* current transfer rate set */
 	u8	desired_speed;	/* desired transfer rate set */
 	u8	pio_mode;	/* for ->set_pio_mode _only_ */
-	u8	dma_mode;	/* for ->dma_pio_mode _only_ */
-        u8	dn;		/* now wide spread use */
+	u8	dma_mode;	/* for ->set_dma_mode _only_ */
+	u8	dn;		/* now wide spread use */
 	u8	acoustic;	/* acoustic management */
 	u8	media;		/* disk, cdrom, tape, floppy, ... */
 	u8	ready_stat;	/* min status value for drive ready */