drm/amdgpu: drop scratch regs save and restore from S3/S4 handling

The expectation is that the base driver doesn't mess with these.
Some components interact with these directly so let the components
handle these directly.
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

@@ -2577,7 +2577,6 @@ int amdgpu_device_suspend(struct drm_device *dev, bool suspend, bool fbcon)
 	 */
 	amdgpu_bo_evict_vram(adev);
 
-	amdgpu_atombios_scratch_regs_save(adev);
 	pci_save_state(dev->pdev);
 	if (suspend) {
 		/* Shut down the device */
@@ -2626,7 +2625,6 @@ int amdgpu_device_resume(struct drm_device *dev, bool resume, bool fbcon)
 		if (r)
 			goto unlock;
 	}
-	amdgpu_atombios_scratch_regs_restore(adev);
 
 	/* post card */
 	if (amdgpu_need_post(adev)) {