[PATCH] Update location of ll_rw_blk.c in docs

Picked from the ubuntu-2.6 tree

The change in location for ll_rw_blk.c from drivers/block/ to block/ caused
failure to generate documentation.

Signed-off-by: Ben Collins <bcollins@ubuntu.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>