mm/page_alloc: remove unused parameter in init_currently_empty_zone()

Commit a2f3aa025766 ("[PATCH] Fix sparsemem on Cell") fixed an oops
experienced on the Cell architecture when init-time functions,
early_*(), are called at runtime by introducing an 'enum memmap_context'
parameter to memmap_init_zone() and init_currently_empty_zone().  This
parameter is intended to be used to tell whether the call of these two
functions is being made on behalf of a hotplug event, or happening at
boot-time.  However, init_currently_empty_zone() does not use this
parameter at all, so remove it.

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
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 0780d11..67d488a 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -339,8 +339,8 @@
 			unsigned long start_pfn, unsigned long num_pages)
 {
 	if (!zone_is_initialized(zone))
-		return init_currently_empty_zone(zone, start_pfn, num_pages,
-						 MEMMAP_HOTPLUG);
+		return init_currently_empty_zone(zone, start_pfn, num_pages);
+
 	return 0;
 }