lightnvm: fix some WARN() messages

WARN_ON() takes a condition, not an error message.  I slightly tweaked
some conditions so hopefully it's more clear.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Matias Bjørling <matias@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/lightnvm/pblk-recovery.c

@@ -167,7 +167,7 @@ static int pblk_recov_l2p_from_emeta(struct pblk *pblk, struct pblk_line *line)
 		if (le64_to_cpu(lba_list[i]) == ADDR_EMPTY) {
 			spin_lock(&line->lock);
 			if (test_and_set_bit(i, line->invalid_bitmap))
-				WARN_ON_ONCE("pblk: rec. double invalidate:\n");
+				WARN_ONCE(1, "pblk: rec. double invalidate:\n");
 			else
 				line->vsc--;
 			spin_unlock(&line->lock);