mm: drop unneeded pgdat argument from free_area_init_node()

free_area_init_node() gets passed in the node id as well as the node
descriptor.  This is redundant as the function can trivially get the node
descriptor itself by means of NODE_DATA() and the node's id.

I checked all the users and NODE_DATA() seems to be usable everywhere
from where this function is called.

Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 833f854..6e26adc 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -455,7 +455,7 @@
 	/* we can use NODE_DATA(nid) from here */
 
 	/* init node's zones as empty zones, we don't have any present pages.*/
-	free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size);
+	free_area_init_node(nid, zones_size, start_pfn, zholes_size);
 
 	return pgdat;
 }