virtio-blk: Fix clean up of host notifiers for single MR transaction.

The code that introduced "virtio-blk: Configure all host notifiers in
a single MR transaction" introduced a second loop variable to perform
cleanup in second loop, but mistakenly still refers to the first
loop variable within the second loop body.

Fixes: d0267da6 ("virtio-blk: Configure all host notifiers in a single MR transaction")
Signed-off-by: Mark Mielke <mark.mielke@gmail.com>
Message-id: CALm7yL08qarOu0dnQkTN+pa=BSRC92g31YpQQNDeAiT4yLZWQQ@mail.gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

hw/block/dataplane/virtio-blk.c

@@ -222,7 +222,7 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
             memory_region_transaction_commit();
 
             while (j--) {
-                virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i);
+                virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), j);
             }
             goto fail_host_notifiers;
         }