This patch is from Nathan Lynch <nathanl@austin.ibm.com>.

This changes struct device_node and associated code to use the kref api for
object refcounting and freeing.  I've given it some testing on pSeries with
cpu add/remove and verified that the release function works.  The change is
somewhat cosmetic but it does make the code easier to understand...  at least
I think so =)

The only real change is that the refcount on all device_nodes is initialized
at 1, and the device node is freed when the refcount reaches 0 (of_remove_node
has the extra "put" to ensure that this happens).  This lets us get rid of the
OF_STALE flag and macros in prom.h.
Signed-off-by: Nathan Lynch <nathanl@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>