mm/page_alloc.c:free_area_init_nodes() fix inappropriate use of enum

Local variable `i' is a) misleadingly-named for an `enum zone_type' and b)
used for indexing zones as well as nodes as well as node_maps.

Make it an `int'.

Reported-by: Frans Pop <[e-mail]>
Cc: Mel Gorman <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

mm/page_alloc.c

···
 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
 {
 	unsigned long nid;
-	enum zone_type i;
+	int i;
 
 	/* Sort early_node_map as initialisation assumes it is sorted */
 	sort_node_map();