mfd: Fix omap_usbhs_alloc_children error handling

1. Return proper error if omap_usbhs_alloc_child fails
2. In the case of goto err_ehci, we should call platform_device_unregister(ehci)
instead of platform_device_put(ehci) because we have already added the
platform device to device hierarchy.

Signed-off-by: Axel Lin <[e-mail]>
Signed-off-by: Axel Lin <[e-mail]>
Tested-by: Keshava Munegowda <[e-mail]>
Acked-by: Felipe Balbi <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>

drivers/mfd/omap-usb-host.c

···
 
 	if (!ehci) {
 		dev_err(dev, "omap_usbhs_alloc_child failed\n");
+		ret = -ENOMEM;
 		goto err_end;
 	}
 
···
 		sizeof(*ohci_data), dev);
 	if (!ohci) {
 		dev_err(dev, "omap_usbhs_alloc_child failed\n");
+		ret = -ENOMEM;
 		goto err_ehci;
 	}
 
 	return 0;
 
 err_ehci:
-	platform_device_put(ehci);
+	platform_device_unregister(ehci);
 
 err_end:
 	return ret;