drm/amdkfd: reserve a fence slot while locking the BO

Looks like the KFD still needs this.
Signed-off-by: Christian König <christian.koenig@amd.com>
Fixes: 8abc1eb2 ("drm/amdkfd: switch over to using drm_exec v3")
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231020123306.43978-1-christian.koenig@amd.com

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

@@ -1103,7 +1103,7 @@ static int reserve_bo_and_vm(struct kgd_mem *mem,
 		if (unlikely(ret))
 			goto error;
 
-		ret = drm_exec_lock_obj(&ctx->exec, &bo->tbo.base);
+		ret = drm_exec_prepare_obj(&ctx->exec, &bo->tbo.base, 1);
 		drm_exec_retry_on_contention(&ctx->exec);
 		if (unlikely(ret))
 			goto error;