lightnvm: pblk: remove unused parameters in pblk_up_rq

The parameters nr_ppas and ppa_list are not used, so remove them.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>