ide: add ide_host_free() helper (take 2)

* Add ide_host_free() helper and convert ide_host_remove() to use it.

* Fix handling of ide_host_register() failure in ide_host_add(),
  icside.c, ide-generic.c, falconide.c and sgiioc4.c.

While at it:

* Fix handling of ide_host_alloc_all() failure in ide-generic.c.

* Fix handling of ide_host_alloc() failure in falconide.c
  (also return the correct error value if no device is found).

v2:
* falconide build fix. (From Stephen Rothwell)

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/sgiioc4.c b/drivers/ide/pci/sgiioc4.c
index 440f43a..42eef19 100644
--- a/drivers/ide/pci/sgiioc4.c
+++ b/drivers/ide/pci/sgiioc4.c
@@ -603,6 +603,7 @@
 	struct ide_host *host;
 	hw_regs_t hw, *hws[] = { &hw, NULL, NULL, NULL };
 	struct ide_port_info d = sgiioc4_port_info;
+	int rc;
 
 	/*  Get the CmdBlk and CtrlBlk Base Registers */
 	bar0 = pci_resource_start(dev, 0);
@@ -638,17 +639,22 @@
 	writel(0x03, (void __iomem *)(irqport + IOC4_INTR_SET * 4));
 
 	host = ide_host_alloc(&d, hws);
-	if (host == NULL)
+	if (host == NULL) {
+		rc = -ENOMEM;
 		goto err;
+	}
 
-	if (ide_host_register(host, &d, hws))
-		return -EIO;
+	rc = ide_host_register(host, &d, hws);
+	if (rc)
+		goto err_free;
 
 	return 0;
+err_free:
+	ide_host_free(host);
 err:
 	release_mem_region(cmd_phys_base, IOC4_CMD_CTL_BLK_SIZE);
 	iounmap(virt_base);
-	return -ENOMEM;
+	return rc;
 }
 
 static unsigned int __devinit