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/pci/cs5530.c b/drivers/ide/pci/cs5530.c
index f235db8..774ff58 100644
--- a/drivers/ide/pci/cs5530.c
+++ b/drivers/ide/pci/cs5530.c
@@ -82,16 +82,18 @@
 {
 	ide_hwif_t *hwif = drive->hwif;
 	ide_drive_t *mate = &hwif->drives[(drive->dn & 1) ^ 1];
-	struct hd_driveid *mateid = mate->id;
+	u16 *mateid = mate->id;
 	u8 mask = hwif->ultra_mask;
 
 	if (mate->present == 0)
 		goto out;
 
-	if ((mateid->capability & 1) && __ide_dma_bad_drive(mate) == 0) {
-		if ((mateid->field_valid & 4) && (mateid->dma_ultra & 7))
+	if ((mate->driveid->capability & 1) && __ide_dma_bad_drive(mate) == 0) {
+		if ((mateid[ATA_ID_FIELD_VALID] & 4) &&
+		    (mateid[ATA_ID_UDMA_MODES] & 7))
 			goto out;
-		if ((mateid->field_valid & 2) && (mateid->dma_mword & 7))
+		if ((mateid[ATA_ID_FIELD_VALID] & 2) &&
+		    (mateid[ATA_ID_MWDMA_MODES] & 7))
 			mask = 0;
 	}
 out: