[PATCH] md: add another COMPAT_IOCTL for md

..  so that you can use bitmaps with 32bit userspace on a 64 bit kernel.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>