lightnvm: pblk: fix write I/O sync stat

Fix stat counter to collect the right number of I/Os being synced on the
completion path.

Fixes: 0880a9aa2d ("lightnvm: pblk: delete redundant buffer pointer")
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/lightnvm/pblk-write.c

@@ -38,7 +38,7 @@ static unsigned long pblk_end_w_bio(struct pblk *pblk, struct nvm_rq *rqd,
 							c_ctx->nr_padded);
 
 #ifdef CONFIG_NVM_DEBUG
-	atomic_long_add(c_ctx->nr_valid, &pblk->sync_writes);
+	atomic_long_add(rqd->nr_ppas, &pblk->sync_writes);
 #endif
 
 	ret = pblk_rb_sync_advance(&pblk->rwb, c_ctx->nr_valid);