sparc64: Fix bootup crash on sun4v.

The DS driver registers as a subsys_initcall() but this can be too
early, in particular this risks registering before we've had a chance
to allocate and setup module_kset in kernel/params.c which is
performed also as a subsyts_initcall().

Register DS using device_initcall() insteal.

Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: stable@vger.kernel.org

arch/sparc/kernel/ds.c

@@ -1264,4 +1264,4 @@ static int __init ds_init(void)
 	return vio_register_driver(&ds_driver);
 }
 
-subsys_initcall(ds_init);
+fs_initcall(ds_init);