dm: open code dm_get_dev_t in dm_init_init

dm_init_init is called from early boot code, and thus lookup_bdev
will never succeed.  Just open code that call to early_lookup_bdev
instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20230531125535.676098-19-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/dm-init.c

@@ -293,8 +293,10 @@ static int __init dm_init_init(void)
 
 	for (i = 0; i < ARRAY_SIZE(waitfor); i++) {
 		if (waitfor[i]) {
+			dev_t dev;
+
 			DMINFO("waiting for device %s ...", waitfor[i]);
-			while (!dm_get_dev_t(waitfor[i]))
+			while (early_lookup_bdev(waitfor[i], &dev))
 				fsleep(5000);
 		}
 	}