stat: add diskutil aggregated sectors to normal output

stat: add diskutil aggregated sectors to normal output

Since we are now collecting sectors in the disk utilization data we
should include them in the aggregated data as well.

I tested this with an LVM mirror. I also tested this on an mdadm mirror
but all the aggregated and slave data was zero.

Fixes: 75cbc26d500fc5f7e36f6203c9b8e08b9c6f007c ("diskutil: Report how
many sectors have been read and written")
Signed-off-by: Vincent Fu <vincent.fu@samsung.com>