drm/amdgpu: move atom scratch setup into amdgpu_atombios.c

There will be a slightly different version for atomfirmware.

Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Ken Wang <Qingqing.Wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
5 files changed