nvme: missing ppaf copy

The ppa format was not copied from the NVMe specific ppa format to the
lightnvm specific ppa format. This led to the ppa format not being
communicated to the layers above.

Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>