hugepage: move is_hugepage_on_freelist inside ifdef to avoid warning

Fixes warning reported by Stephen Rothwell

mm/hugetlb.c:2950: warning: 'is_hugepage_on_freelist' defined but not used

for the !CONFIG_MEMORY_FAILURE case.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>

mm/hugetlb.c

@@ -2946,6 +2946,8 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
 	hugetlb_acct_memory(h, -(chg - freed));
 }
 
+#ifdef CONFIG_MEMORY_FAILURE
+
 /* Should be called in hugetlb_lock */
 static int is_hugepage_on_freelist(struct page *hpage)
 {
@@ -2960,7 +2962,6 @@ static int is_hugepage_on_freelist(struct page *hpage)
 	return 0;
 }
 
-#ifdef CONFIG_MEMORY_FAILURE
 /*
  * This function is called from memory failure code.
  * Assume the caller holds page lock of the head page.