[PATCH] block cleanups: Add kconfig default iosched submenu

Add a kconfig submenu to select the default I/O scheduler, in case
anticipatory is not compiled in or another default is preferred.  Also,
since no-op is always available, we should use it whenever the selected
default is not.

Signed-off-by: Nate Diller <nate@namesys.com>
Acked-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>