of/platform: remove all of_bus_type and of_platform_bus_type references

Both of_bus_type and of_platform_bus_type are just #define aliases
for the platform bus.  This patch removes all references to them and
switches to the of_register_platform_driver()/of_unregister_platform_driver()
API for registering.

Subsequent patches will convert each user of of_register_platform_driver()
into plain platform_drivers without the of_platform_driver shim.  At which
point the of_register_platform_driver()/of_unregister_platform_driver()
functions can be removed.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/video/cg14.c b/drivers/video/cg14.c
index e5dc224..d09fde8 100644
--- a/drivers/video/cg14.c
+++ b/drivers/video/cg14.c
@@ -610,12 +610,12 @@
 	if (fb_get_options("cg14fb", NULL))
 		return -ENODEV;
 
-	return of_register_driver(&cg14_driver, &of_bus_type);
+	return of_register_platform_driver(&cg14_driver);
 }
 
 static void __exit cg14_exit(void)
 {
-	of_unregister_driver(&cg14_driver);
+	of_unregister_platform_driver(&cg14_driver);
 }
 
 module_init(cg14_init);