virtio-blk: Fix potential nullpointer read access in virtio_blk_data_plane_destroy

Fixes: CID 1532828
Fixes: b6948ab01d ("virtio-blk: add iothread-vq-mapping parameter")
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
1 file changed