drm/amdgpu: Add GMC 9.0 support (v2)

On SOC-15 parts, the GMC (Graphics Memory Controller) consists
of two hubs: GFX (graphics and compute) and MM (sdma, uvd, vce).

v2: drop sdma from Makefile, fix duplicate return statement.

Signed-off-by: Alex Xie <AlexBin.Xie@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile b/drivers/gpu/drm/amd/amdgpu/Makefile
index 4ae5ddc..ccbc4c0 100644
--- a/drivers/gpu/drm/amd/amdgpu/Makefile
+++ b/drivers/gpu/drm/amd/amdgpu/Makefile
@@ -39,7 +39,8 @@
 # add GMC block
 amdgpu-y += \
 	gmc_v7_0.o \
-	gmc_v8_0.o
+	gmc_v8_0.o \
+	gfxhub_v1_0.o mmhub_v1_0.o gmc_v9_0.o
 
 # add IH block
 amdgpu-y += \