drm/amdgpu: do not set nil entry in compute_prio_sched

If there are no high priority compute queues available then set normal
priority sched array to compute_prio_sched[AMDGPU_GFX_PIPE_PRIO_HIGH]
Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c

@@ -686,10 +686,17 @@ static void amdgpu_ctx_init_compute_sched(struct amdgpu_device *adev)
 	adev->gfx.num_compute_sched[i] = num_compute_sched_normal;
 
 	i = AMDGPU_GFX_PIPE_PRIO_HIGH;
+	if (num_compute_sched_high == (AMDGPU_MAX_COMPUTE_RINGS - 1)) {
+		/* When compute has no high priority rings then use */
+		/* normal priority sched array */
+		adev->gfx.compute_prio_sched[i] = &adev->gfx.compute_sched[0];
+		adev->gfx.num_compute_sched[i] = num_compute_sched_normal;
+	} else {
 		adev->gfx.compute_prio_sched[i] =
 			&adev->gfx.compute_sched[num_compute_sched_high - 1];
 		adev->gfx.num_compute_sched[i] =
 			adev->gfx.num_compute_rings - num_compute_sched_normal;
+	}
 }
 
 void amdgpu_ctx_init_sched(struct amdgpu_device *adev)