drm/amdgpu/athub2: enable athub2 clock gating

Enable athub2 clock gating and light sleep

Signed-off-by: Jack Xiao <Jack.Xiao@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/Makefile

@@ -135,6 +135,10 @@ amdgpu-y += \
 	amdgpu_vcn.o \
 	vcn_v1_0.o
 
+# add ATHUB block
+amdgpu-y += \
+	athub_v2_0.o
+
 # add amdkfd interfaces
 amdgpu-y += amdgpu_amdkfd.o