[flang][OpenMP] Extend `do concurrent` mapping to device (#155987)
Upstreams further parts of `do concurrent` to OpenMP conversion pass
from AMD's fork. This PR extends the pass by adding support for mapping
to the device.
PR stack:
- https://github.com/llvm/llvm-project/pull/155754
- https://github.com/llvm/llvm-project/pull/155987 ◀️
- https://github.com/llvm/llvm-project/pull/155992
- https://github.com/llvm/llvm-project/pull/155993
- https://github.com/llvm/llvm-project/pull/157638
- https://github.com/llvm/llvm-project/pull/156610
- https://github.com/llvm/llvm-project/pull/156837