[clang] [HIP] Move HIP to the new driver by default (PR #123359)

[Henry Linjamäki via cfe-commits]

linehill wrote:

Sorry for the delayed response - I have been on a long vacation.

I’m not familiar with the new offload driver internals to give pointers on what needs to be changed and where for retaining the custom plugin and linker behavior needed by the [chipStar](https://github.com/CHIP-SPV/chipStar) nor I can devote time to look at it currently. 

Perhaps, the HIPSPV toolchain could default to the old offload driver in the meantime until I or someone else takes a look at it. 

cc @pjaaskel and @pvelesko for awareness.

https://github.com/llvm/llvm-project/pull/123359