ntfs: kernel-doc warning fixes

cached_page and lru_pvec were removed from ntfs_attr_extend_initialized
in commit 2ec93b0b ("ntfs: clean up ntfs_attr_extend_initialized")

lru_pvec has been removed from __ntfs_grab_cache_pages in commit
4c99000a

 ("ntfs: use add_to_page_cache_lru()")

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-by: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>