drm/virtio: fix possible leak/unlock virtio_gpu_object_array

virtio_gpu_object array is not freed or unlocked in some
failed cases.

Signed-off-by: xndcn <xndchn@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20210305151819.14330-1-xndchn@gmail.com


Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>