drm/amdgpu: Clear build undefined warning

Add amdgpu_amdkfd_arcturus_get_functions stub when
CONFIG_HSA_AMD is undefinded.
Signed-off-by: James Zhu <James.Zhu@amd.com>
Reviewed-by: Yong Zhao <Yong.Zhao@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -718,6 +718,11 @@ struct kfd2kgd_calls *amdgpu_amdkfd_gfx_9_0_get_functions(void)
 	return NULL;
 }
 
+struct kfd2kgd_calls *amdgpu_amdkfd_arcturus_get_functions(void)
+{
+	return NULL;
+}
+
 struct kfd2kgd_calls *amdgpu_amdkfd_gfx_10_0_get_functions(void)
 {
 	return NULL;