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/arch/arm/mm/init.c b/arch/arm/mm/init.c
index b657f17..e635294 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -284,7 +284,7 @@
 	 */
 	arch_adjust_zones(node, zone_size, zhole_size);
 
-	free_area_init_node(node, pgdat, zone_size, start_pfn, zhole_size);
+	free_area_init_node(node, zone_size, start_pfn, zhole_size);
 
 	return end_pfn;
 }