early_pfn_to_nid needs to be __meminit

Since it is referenced by memmap_init_zone (which is __meminit) via the
early_pfn_in_nid macro when CONFIG_NODES_SPAN_OTHER_NODES is set (which
basically means PowerPC 64).

This removes a section mismatch warning in those circumstances.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -2284,7 +2284,7 @@ static int __meminit next_active_region_index_in_nid(int index, int nid)
  * was used and there are no special requirements, this is a convenient
  * alternative
  */
-int __init early_pfn_to_nid(unsigned long pfn)
+int __meminit early_pfn_to_nid(unsigned long pfn)
 {
 	int i;