drm/amdgpu: skip kfd-iommu suspend/resume for S0ix

GFX is in gfxoff mode during s0ix so we shouldn't need to
actually execute kfd_iommu_suspend/kfd_iommu_resume operation.
Signed-off-by: Aaron Liu <aaron.liu@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -3305,9 +3305,11 @@ static int amdgpu_device_ip_resume(struct amdgpu_device *adev)
 {
 	int r;
 
+	if (!adev->in_s0ix) {
 		r = amdgpu_amdkfd_resume_iommu(adev);
 		if (r)
 			return r;
+	}
 
 	r = amdgpu_device_ip_resume_phase1(adev);
 	if (r)