mfd: omap-usb-host: Fix dts probe of children

It currently only works if the parent bus uses "simple-bus". We
currently try to probe children with non-existing compatible values.
And we're missing .probe.

I noticed this while testing devices configured to probe using ti-sysc
interconnect target module driver. For that we also may want to rebind
the driver, so let's remove __init and __exit.

Signed-off-by: Tony Lindgren <[e-mail]>
Acked-by: Roger Quadros <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/omap-usb-host.c

···
 }
 
 static const struct of_device_id usbhs_child_match_table[] = {
-	{ .compatible = "ti,omap-ehci", },
-	{ .compatible = "ti,omap-ohci", },
+	{ .compatible = "ti,ehci-omap", },
+	{ .compatible = "ti,ohci-omap3", },
 	{ }
 };
 
···
 		.pm		= &usbhsomap_dev_pm_ops,
 		.of_match_table = usbhs_omap_dt_ids,
 	},
+	.probe		= usbhs_omap_probe,
 	.remove		= usbhs_omap_remove,
 };
 
···
 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("usb host common core driver for omap EHCI and OHCI");
 
-static int __init omap_usbhs_drvinit(void)
+static int omap_usbhs_drvinit(void)
 {
-	return platform_driver_probe(&usbhs_omap_driver, usbhs_omap_probe);
+	return platform_driver_register(&usbhs_omap_driver);
 }
 
 /*
···
  */
 fs_initcall_sync(omap_usbhs_drvinit);
 
-static void __exit omap_usbhs_drvexit(void)
+static void omap_usbhs_drvexit(void)
 {
 	platform_driver_unregister(&usbhs_omap_driver);
 }