feat(ck): Add gfx90c build support
## Motivation
Needed for https://github.com/ROCm/TheRock/issues/3818.
## Technical Details
When building torch w/ TheRock CI (`build_prod_wheels.py`) on gfx90c,
was running into the generic error below compiling
`amd_buffer_addressing_builtins.hpp`
```
composable_kernel/include/ck/utility/amd_buffer_addressing_builtins.hpp:33:48: error: use of undeclared identifier 'CK_BUFFER_RESOURCE_3RD_DWORD'
...:61:22: error: use of undeclared identifier 'CK_BUFFER_RESOURCE_3RD_DWORD'
...:73:22: error: use of undeclared identifier 'CK_BUFFER_RESOURCE_3RD_DWORD'
4 errors generated when compiling for gfx90c.
```
Adding `__gfx90c__` to the arch definition list resolves this.
## Test Plan
Build torch (`build_prod_wheels.py`) for gfx90c before and after patch.
## Test Result
- Before: Fails with `amd_buffer_addressing_builtins.hpp:33:48: error: use of undeclared identifier 'CK_BUFFER_RESOURCE_3RD_DWORD'`
- After: Build passes
## Submission Checklist
- [ ] Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.
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