drm/amdgpu: add support for athub v2.1

Add athub v2.1 function and support to compile it.

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

drivers/gpu/drm/amd/amdgpu/Makefile

@@ -163,7 +163,8 @@ amdgpu-y += \
 # add ATHUB block
 amdgpu-y += \
 	athub_v1_0.o \
-	athub_v2_0.o
+	athub_v2_0.o \
+	athub_v2_1.o
 
 # add amdkfd interfaces
 amdgpu-y += amdgpu_amdkfd.o