rmap: make anon_vma_chain_free() static

Make anon_vma_chain_free() static.  It is called only in rmap.c and the
corresponding alloc function is already static.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/rmap.c

@@ -80,7 +80,7 @@ static inline struct anon_vma_chain *anon_vma_chain_alloc(void)
 	return kmem_cache_alloc(anon_vma_chain_cachep, GFP_KERNEL);
 }
 
-void anon_vma_chain_free(struct anon_vma_chain *anon_vma_chain)
+static void anon_vma_chain_free(struct anon_vma_chain *anon_vma_chain)
 {
 	kmem_cache_free(anon_vma_chain_cachep, anon_vma_chain);
 }