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/pci/cmd640.c b/drivers/ide/pci/cmd640.c
index 013697b..e6c6200 100644
--- a/drivers/ide/pci/cmd640.c
+++ b/drivers/ide/pci/cmd640.c
@@ -709,7 +709,6 @@
  */
 static int __init cmd640x_init(void)
 {
-	struct ide_host *host;
 	int second_port_cmd640 = 0, rc;
 	const char *bus_type, *port2;
 	u8 b, cfr;
@@ -829,11 +828,7 @@
 	cmd640_dump_regs();
 #endif
 
-	host = ide_host_alloc(&cmd640_port_info, hws);
-	if (host)
-		ide_host_register(host, &cmd640_port_info, hws);
-
-	return 1;
+	return ide_host_add(&cmd640_port_info, hws, NULL);
 }
 
 module_param_named(probe_vlb, cmd640_vlb, bool, 0);