drm/amdgpu: add burst_nop flag for sdma

The burst NOP is supported for SDMA when feature_version is >= 20.

Signed-off-by: Jammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index b66938d..34812ec 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1708,6 +1708,7 @@
 	uint32_t		feature_version;
 
 	struct amdgpu_ring	ring;
+	bool			burst_nop;
 };
 
 /*