ide: make drive->id an union (take 2)

Make drive->id an unnamed union so id can be accessed either by using
'u16 *id' or 'struct hd_driveid *driveid'.  Then convert all existing
drive->id users accordingly (using 'u16 *id' when possible).

This is an intermediate step to make ide 'struct hd_driveid'-free.

While at it:

- Add missing KERN_CONTs in it821x.c.

- Use ATA_ID_WORDS and ATA_ID_*_LEN defines.

- Remove unnecessary checks for drive->id.

- s/drive_table/table/ in ide_in_drive_list().

- Cleanup ide_config_drive_speed() a bit.

- s/drive1/dev1/ & s/drive0/dev0/ in ide_undecoded_slave().

v2:
Fix typo in drivers/ide/ppc/pmac.c. (From Stephen Rothwell)

There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-proc.c

@@ -561,11 +561,10 @@ static int proc_ide_read_dmodel
 	(char *page, char **start, off_t off, int count, int *eof, void *data)
 {
 	ide_drive_t	*drive = (ide_drive_t *) data;
-	struct hd_driveid *id = drive->id;
+	char		*m = (char *)&drive->id[ATA_ID_PROD];
 	int		len;
 
-	len = sprintf(page, "%.40s\n",
-		(id && id->model[0]) ? (char *)id->model : "(none)");
+	len = sprintf(page, "%.40s\n", m[0] ? m : "(none)");
 	PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
 }