ide: add ide_deprecated_find_port() helper

* Factor out code for finding ide_hwifs[] slot from ide_register_hw()
  to ide_deprecated_find_port().

* Convert bast-ide, ide-cs and delkin_cb host drivers to use ide_device_add()
  instead of ide_register_hw() (while at it drop doing "ide_unregister()" loop
  which tries to unregister _all_ IDE interfaces if useable ide_hwifs[] slot
  cannot be find).

This patch leaves us with only two ide_register_hw() users:
- drivers/macintosh/mediabay.c
- drivers/ide/ide.c

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index 166acd5..d42216b 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -683,6 +683,31 @@
 }
 EXPORT_SYMBOL_GPL(ide_init_port_hw);
 
+ide_hwif_t *ide_deprecated_find_port(unsigned long base)
+{
+	ide_hwif_t *hwif;
+	int i;
+
+	for (i = 0; i < MAX_HWIFS; i++) {
+		hwif = &ide_hwifs[i];
+		if (hwif->io_ports[IDE_DATA_OFFSET] == base)
+			goto found;
+	}
+
+	for (i = 0; i < MAX_HWIFS; i++) {
+		hwif = &ide_hwifs[i];
+		if (hwif->hold)
+			continue;
+		if (!hwif->present && hwif->mate == NULL)
+			goto found;
+	}
+
+	hwif = NULL;
+found:
+	return hwif;
+}
+EXPORT_SYMBOL_GPL(ide_deprecated_find_port);
+
 /**
  *	ide_register_hw		-	register IDE interface
  *	@hw: hardware registers
@@ -702,18 +727,10 @@
 	u8 idx[4] = { 0xff, 0xff, 0xff, 0xff };
 
 	do {
-		for (index = 0; index < MAX_HWIFS; ++index) {
-			hwif = &ide_hwifs[index];
-			if (hwif->io_ports[IDE_DATA_OFFSET] == hw->io_ports[IDE_DATA_OFFSET])
-				goto found;
-		}
-		for (index = 0; index < MAX_HWIFS; ++index) {
-			hwif = &ide_hwifs[index];
-			if (hwif->hold)
-				continue;
-			if (!hwif->present && hwif->mate == NULL)
-				goto found;
-		}
+		hwif = ide_deprecated_find_port(hw->io_ports[IDE_DATA_OFFSET]);
+		index = hwif->index;
+		if (hwif)
+			goto found;
 		for (index = 0; index < MAX_HWIFS; index++)
 			ide_unregister(index, 1, 1);
 	} while (retry--);