nouveau: set placement to original placement on uvmm validate.

When a buffer is evicted for memory pressure or TTM evict all,
the placement is set to the eviction domain, this means the
buffer never gets revalidated on the next exec to the correct domain.

I think this should be fine to use the initial domain from the
object creation, as least with VM_BIND this won't change after
init so this should be the correct answer.

Fixes: b88baab8 ("drm/nouveau: implement new VM_BIND uAPI")
Cc: Danilo Krummrich <dakr@redhat.com>
Cc: <stable@vger.kernel.org> # v6.6
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240515025542.2156774-1-airlied@gmail.com

drivers/gpu/drm/nouveau/nouveau_uvmm.c

@@ -1803,6 +1803,7 @@ nouveau_uvmm_bo_validate(struct drm_gpuvm_bo *vm_bo, struct drm_exec *exec)
 {
 	struct nouveau_bo *nvbo = nouveau_gem_object(vm_bo->obj);
 
+	nouveau_bo_placement_set(nvbo, nvbo->valid_domains, 0);
 	return nouveau_bo_validate(nvbo, true, false);
 }