ubi: block: Fix missing blk_mq_end_request

Switching to BLK_MQ_F_BLOCKING wrongly removed the call to
blk_mq_end_request(). Add it back to have our IOs finished

Fixes: 91cc8fbc ("ubi: block: set BLK_MQ_F_BLOCKING")
Analyzed-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Daniel Palmer <daniel@0x0f.com>
Link: https://lore.kernel.org/linux-mtd/CAHk-=wi29bbBNh3RqJKu3PxzpjDN5D5K17gEVtXrb7-6bfrnMQ@mail.gmail.com/Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Daniel Palmer <daniel@0x0f.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/mtd/ubi/block.c

@@ -221,7 +221,10 @@ static blk_status_t ubiblock_read(struct request *req)
 
 	rq_for_each_segment(bvec, req, iter)
 		flush_dcache_page(bvec.bv_page);
-	return errno_to_blk_status(ret);
+
+	blk_mq_end_request(req, errno_to_blk_status(ret));
+
+	return BLK_STS_OK;
 }
 
 static int ubiblock_open(struct block_device *bdev, fmode_t mode)