mm: meminit: mark init_reserved_page as __meminit

The function is called from __meminit context and calls other __meminit
functions but isn't it self mark as such today:

  WARNING: vmlinux.o(.text.unlikely+0x4516): Section mismatch in reference from the function init_reserved_page() to the function .meminit.text:early_pfn_to_nid()
  The function init_reserved_page() references the function __meminit early_pfn_to_nid().
  This is often because init_reserved_page lacks a __meminit annotation or the annotation of early_pfn_to_nid is wrong.

On most compilers, we don't notice this because the function gets
inlined all the time.  Adding __meminit here fixes the harmless warning
for the old versions and is generally the correct annotation.

Link: http://lkml.kernel.org/r/[email protected]
Fixes: 7e18adb4f80b ("mm: meminit: initialise remaining struct pages in parallel with kswapd")
Signed-off-by: Arnd Bergmann <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c841af8..38d165a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1190,7 +1190,7 @@ static void __meminit __init_single_pfn(unsigned long pfn, unsigned long zone,
 }
 
 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
-static void init_reserved_page(unsigned long pfn)
+static void __meminit init_reserved_page(unsigned long pfn)
 {
 	pg_data_t *pgdat;
 	int nid, zid;