Since pblk registers its own block device, the iostat accounting is
not automatically done for us. Therefore, add the necessary
accounting logic to satisfy the iostat interface.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <m@bjorling.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>