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/pci_sabre.c b/arch/sparc/kernel/pci_sabre.c
index 99c6dba..2d7bf30 100644
--- a/arch/sparc/kernel/pci_sabre.c
+++ b/arch/sparc/kernel/pci_sabre.c
@@ -606,7 +606,7 @@
 
 static int __init sabre_init(void)
 {
-	return of_register_driver(&sabre_driver, &of_bus_type);
+	return of_register_platform_driver(&sabre_driver);
 }
 
 subsys_initcall(sabre_init);