do_mpage_readpage(): remove useless clear_buffer_mapped() call

It is known that buffer_mapped() is false in this code path.
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/mpage.c

@@ -241,7 +241,6 @@ do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
 				first_hole = page_block;
 			page_block++;
 			block_in_file++;
-			clear_buffer_mapped(map_bh);
 			continue;
 		}