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/arch/sparc/kernel/time_32.c b/arch/sparc/kernel/time_32.c
index e404b06..5dc2021 100644
--- a/arch/sparc/kernel/time_32.c
+++ b/arch/sparc/kernel/time_32.c
@@ -189,7 +189,7 @@
 /* Probe for the mostek real time clock chip. */
 static int __init clock_init(void)
 {
-	return of_register_driver(&clock_driver, &of_platform_bus_type);
+	return of_register_platform_driver(&clock_driver);
 }
 /* Must be after subsys_initcall() so that busses are probed.  Must
  * be before device_initcall() because things like the RTC driver