drm/amdkfd: Added gfx_v12_kfd2kgd interface for GFX12.

Initial implementation, based on GFX11.

v2: Removed functions not needed by cp scheduler.
v3: Fixed typos.
v4: squash in warning fix (Alex)

Signed-off-by: David Belanger <david.belanger@amd.com>
Acked-by: Jonathan Kim <jonathan.kim@amd.com>
Reviewed-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>