[clang] [Driver] Reject unsupported -mcmodel= (PR #70262)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> > This is not being handled for AMDGPU Targets.
> 
> I'm assuming this is an artifact of passing all arguments both the host target and the offload target? @jhuber6 what's the correct way of filtering out irrelevant codegen options?

I don't know what the desired behavior is. The `Triple` being used here should match the one from the ToolChain. So, it should be `amdgpu` when doing the device side compilation. If we need to change behavior based off of offloading language, you check the JobAction for its `OffloadKind`.

https://github.com/llvm/llvm-project/pull/70262