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 <axel.lin@gmail.com>
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Tested-by: Keshava Munegowda <keshava_mgowda@ti.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/omap-usb-host.c

@@ -281,6 +281,7 @@ static int omap_usbhs_alloc_children(struct platform_device *pdev)
 
 	if (!ehci) {
 		dev_err(dev, "omap_usbhs_alloc_child failed\n");
+		ret = -ENOMEM;
 		goto err_end;
 	}
 
@@ -304,13 +305,14 @@ static int omap_usbhs_alloc_children(struct platform_device *pdev)
 		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;