mm: remove struct node_active_region

struct node_active_region is not used anymore.  Remove it.
Signed-off-by: minkyung88.kim <minkyung88.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mmzone.h

@@ -690,14 +690,6 @@ struct zonelist {
 #endif
 };
 
-#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
-struct node_active_region {
-	unsigned long start_pfn;
-	unsigned long end_pfn;
-	int nid;
-};
-#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
-
 #ifndef CONFIG_DISCONTIGMEM
 /* The array of struct pages - for discontigmem use pgdat->lmem_map */
 extern struct page *mem_map;