drm/amdgpu: use function pointer for gfxhub functions

gfxhub functions are now called from function pointers,
instead of from asic-specific functions.

Signed-off-by: Oak Zeng <Oak.Zeng@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

@@ -104,6 +104,7 @@
 #include "amdgpu_mes.h"
 #include "amdgpu_umc.h"
 #include "amdgpu_mmhub.h"
+#include "amdgpu_gfxhub.h"
 #include "amdgpu_df.h"
 
 #define MAX_GPU_INSTANCE		16
@@ -881,6 +882,9 @@ struct amdgpu_device {
 	/* mmhub */
 	struct amdgpu_mmhub		mmhub;
 
+	/* gfxhub */
+	struct amdgpu_gfxhub		gfxhub;
+
 	/* gfx */
 	struct amdgpu_gfx		gfx;