mtd: Fixed breaking list in __mtd_del_partition.

Not the child partition should be removed from the partition list
but the partition itself. Otherwise the partition list gets broken
and any subsequent remove operations leads to a kernel panic.

Fixes: 46b5889cc2c5 ("mtd: implement proper partition handling")
Signed-off-by: Andreas Oetken <[e-mail]>
Cc: [e-mail]
Signed-off-by: Miquel Raynal <[e-mail]>
Link: https://lore.kernel.org/linux-mtd/[e-mail]

drivers/mtd/mtdpart.c

···
 	if (err)
 		return err;
 
-	list_del(&child->part.node);
+	list_del(&mtd->part.node);
 	free_partition(mtd);
 
 	return 0;