linux-next: build failure after merge of the bluetooth tree

Hi all,

After merging the bluetooth tree, today's linux-next build (x86_64
allmodconfig) failed like this:

In file included from <command-line>:32:
./usr/include/linux/virtio_bt.h:1:1: error: C++ style comments are not allowed in ISO C90
    1 | // SPDX-License-Identifier: BSD-3-Clause
      | ^
./usr/include/linux/virtio_bt.h:1:1: note: (this will be reported only once per input file)

Caused by commit

  148a48f61393 ("Bluetooth: Add support for virtio transport driver")

I have used the bluetooth tree from next-20210407 for today.

-- 
Cheers,
Stephen Rothwell