[POWERPC] bootwrapper: flatdevtree fixes

1. ft_create_node was returning the internal pointer rather than a phandle.
2. ft_find_device_rel was treating a "top" phandle of NULL as an error,
rather than as the root of the tree.  The old, absolute ft_find_device
is removed, and the relative version is renamed to ft_find_device().

Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/boot/flatdevtree_misc.c

@@ -18,7 +18,7 @@ static struct ft_cxt cxt;
 
 static void *fdtm_finddevice(const char *name)
 {
-	return ft_find_device(&cxt, name);
+	return ft_find_device(&cxt, NULL, name);
 }
 
 static int fdtm_getprop(const void *phandle, const char *propname,