drm/amdgpu: support cond exec

This adds the groundwork for conditional execution on
SDMA which is necessary for preemption.

Signed-off-by: Monk Liu <monk.liu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-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 2c2f234..49adb45 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -788,6 +788,9 @@
 	struct amdgpu_ctx	*current_ctx;
 	enum amdgpu_ring_type	type;
 	char			name[16];
+	unsigned		cond_exe_offs;
+	u64				cond_exe_gpu_addr;
+	volatile u32	*cond_exe_cpu_addr;
 };
 
 /*