block: remove a pointless call to MINOR() in device_add_disk

blk_alloc_ext_minor already returns just a minor number, so no need to
mask the high bits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210824075216.1179406-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/genhd.c

@@ -457,7 +457,7 @@ int device_add_disk(struct device *parent, struct gendisk *disk,
 		if (ret < 0)
 			return ret;
 		disk->major = BLOCK_EXT_MAJOR;
-		disk->first_minor = MINOR(ret);
+		disk->first_minor = ret;
 		disk->flags |= GENHD_FL_EXT_DEVT;
 	}