[PATCH] md: fix sizing problem with raid5-reshape and CONFIG_LBD=n

I forgot to has the size-in-blocks to (loff_t) before shifting up to a
size-in-bytes.

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