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>
diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index 7724516..8d3fab3 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -328,7 +328,7 @@
 	if (arg < 0 || arg > 1)
 		return -EINVAL;
 
-	if (!drive->id || !(drive->id->capability & 1))
+	if ((drive->driveid->capability & 1) == 0)
 		goto out;
 
 	if (hwif->dma_ops == NULL)
@@ -710,21 +710,21 @@
 			  char *buf)
 {
 	ide_drive_t *drive = to_ide_device(dev);
-	return sprintf(buf, "%s\n", drive->id->model);
+	return sprintf(buf, "%s\n", (char *)&drive->id[ATA_ID_PROD]);
 }
 
 static ssize_t firmware_show(struct device *dev, struct device_attribute *attr,
 			     char *buf)
 {
 	ide_drive_t *drive = to_ide_device(dev);
-	return sprintf(buf, "%s\n", drive->id->fw_rev);
+	return sprintf(buf, "%s\n", (char *)&drive->id[ATA_ID_FW_REV]);
 }
 
 static ssize_t serial_show(struct device *dev, struct device_attribute *attr,
 			   char *buf)
 {
 	ide_drive_t *drive = to_ide_device(dev);
-	return sprintf(buf, "%s\n", drive->id->serial_no);
+	return sprintf(buf, "%s\n", (char *)&drive->id[ATA_ID_SERNO]);
 }
 
 static struct device_attribute ide_dev_attrs[] = {