ide: add ide_host_add() helper

Add ide_host_add() helper which does ide_host_alloc()+ide_host_register(),
then convert ide_setup_pci_device[s](), ide_legacy_device_add() and some
host drivers to use it.

While at it:

* Fix ide_setup_pci_device[s](), ide_arm.c, gayle.c, ide-4drives.c,
  macide.c, q40ide.c, cmd640.c and cs5520.c to return correct error value.

* -ENOENT -> -ENOMEM in rapide.c, ide-h8300.c, ide-generic.c, au1xxx-ide.c
  and pmac.c

* -ENODEV -> -ENOMEM in palm_bk3710.c, ide_platform.c and delkin_cb.c

* -1 -> -ENOMEM in ide-pnp.c

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ppc/pmac.c b/drivers/ide/ppc/pmac.c
index ecd2f28..c521bf6 100644
--- a/drivers/ide/ppc/pmac.c
+++ b/drivers/ide/ppc/pmac.c
@@ -1043,6 +1043,7 @@
 	ide_hwif_t *hwif;
 	hw_regs_t *hws[] = { hw, NULL, NULL, NULL };
 	struct ide_port_info d = pmac_port_info;
+	int rc;
 
 	pmif->broken_dma = pmif->broken_dma_warn = 0;
 	if (of_device_is_compatible(np, "shasta-ata")) {
@@ -1118,11 +1119,9 @@
 			 pmif->mdev ? "macio" : "PCI", pmif->aapl_bus_id,
 			 pmif->mediabay ? " (mediabay)" : "", hw->irq);
 
-	host = ide_host_alloc(&d, hws);
-	if (host == NULL)
-		return -ENOENT;
-
-	ide_host_register(host, &d, hws);
+	rc = ide_host_add(&d, hws, &host);
+	if (rc)
+		return rc;
 
 	hwif = host->ports[0];