can: virtio: Fix comment in UAPI header

can: virtio: Fix comment in UAPI header

When compile testing the UAPI headers with clang, there is an warning turned
error for using a C++ style ('//') comment, which is explicitly forbidden for
UAPI headers.

  In file included from <built-in>:1:
  ./usr/include/linux/virtio_can.h:29:35: error: // comments are not allowed in this language [-Werror,-Wcomment]
     29 | #define VIRTIO_CAN_MAX_DLEN    64 // this is like CANFD_MAX_DLEN
        |                                   ^
  1 error generated.

Switch to a standard C style comment.

Fixes: 2b6b4bb7d96f ("can: virtio: Add virtio CAN driver")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20260604-virtio_can-fix-uapi-comment-v1-1-199fa96ec5f0@kernel.org>