DPC++ daily 2022-11-07

[SYCL][HIP] Add interop header and devcie specialization (#7145)

Fixes https://github.com/intel/llvm/issues/6635 for HIP.

Note that it does mean the HIP extension header must be included in user
applications in order to get the correct specialization, as is done in
the test:

```cpp
#include <sycl/ext/oneapi/backend/hip.hpp>
```