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/include/linux/mm.h b/include/linux/mm.h
index f807109..196924b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -962,9 +962,8 @@
 		NULL: pte_offset_kernel(pmd, address))
 
 extern void free_area_init(unsigned long * zones_size);
-extern void free_area_init_node(int nid, pg_data_t *pgdat,
-	unsigned long * zones_size, unsigned long zone_start_pfn, 
-	unsigned long *zholes_size);
+extern void free_area_init_node(int nid, unsigned long * zones_size,
+		unsigned long zone_start_pfn, unsigned long *zholes_size);
 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
 /*
  * With CONFIG_ARCH_POPULATES_NODE_MAP set, an architecture may initialise its