drm/amdgpu: fix amdgpu_mn_unlock() in the CS error path

Avoid unlocking a lock we never locked.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1247,10 +1247,10 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
 error_abort:
 	dma_fence_put(&job->base.s_fence->finished);
 	job->base.s_fence = NULL;
+	amdgpu_mn_unlock(p->mn);
 
 error_unlock:
 	amdgpu_job_free(job);
-	amdgpu_mn_unlock(p->mn);
 	return r;
 }