Move the 4-byte `capabilities' field next to other 4-byte things.
Shrinks sizeof(backing_dev_info) by 8 bytes on x86_64.
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>