ide: merge ide_hwgroup_t with ide_hwif_t (v2)

* Merge ide_hwgroup_t with ide_hwif_t.

* Cleanup init_irq() accordingly, then remove no longer needed
  ide_remove_port_from_hwgroup() and ide_ports[].

* Remove now unused HWGROUP() macro.

While at it:

* ide_dump_ata_error() fixups

v2:
* Fix ->quirk_list check in do_ide_request()
  (s/hwif->cur_dev/prev_port->cur_dev).

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c
index fffd117..72ebab0 100644
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -96,7 +96,7 @@
 
 	if (OK_STAT(stat, DRIVE_READY, drive->bad_wstat | ATA_DRQ)) {
 		if (!dma_stat) {
-			struct request *rq = hwif->hwgroup->rq;
+			struct request *rq = hwif->rq;
 
 			task_end_request(drive, rq, stat);
 			return ide_stopped;