mm: Fix out-of-date comments which refers non-existent functions

do_file_page and do_no_page don't exist anymore, but some comments
still refers them. The patch fixes them by replacing them with
existing ones.

Signed-off-by: Ryota Ozaki <ozaki.ryota@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/arch/avr32/mm/cache.c b/arch/avr32/mm/cache.c
index 24a74d1..6a46ecd 100644
--- a/arch/avr32/mm/cache.c
+++ b/arch/avr32/mm/cache.c
@@ -113,7 +113,7 @@
 }
 
 /*
- * This one is called from do_no_page(), do_swap_page() and install_page().
+ * This one is called from __do_fault() and do_swap_page().
  */
 void flush_icache_page(struct vm_area_struct *vma, struct page *page)
 {