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/ide-generic.c b/drivers/ide/ide-generic.c
index e881836..a7082c2 100644
--- a/drivers/ide/ide-generic.c
+++ b/drivers/ide/ide-generic.c
@@ -28,9 +28,8 @@
 
 static ssize_t store_add(struct class *cls, const char *buf, size_t n)
 {
-	struct ide_host *host;
 	unsigned int base, ctl;
-	int irq;
+	int irq, rc;
 	hw_regs_t hw, *hws[] = { &hw, NULL, NULL, NULL };
 
 	if (sscanf(buf, "%x:%x:%d", &base, &ctl, &irq) != 3)
@@ -41,11 +40,9 @@
 	hw.irq = irq;
 	hw.chipset = ide_generic;
 
-	host = ide_host_alloc(NULL, hws);
-	if (host == NULL)
-		return -ENOENT;
-
-	ide_host_register(host, NULL, hws);
+	rc = ide_host_add(NULL, hws, NULL);
+	if (rc)
+		return rc;
 
 	return n;
 };