drm/ttm/tests: fix lru_count ASSERT

On pool init we should expect the lru_count for each node to be zeroed
as per __list_lru_init -> init_one_lru, but here we are asserting the
opposite.

Currently our CI is blowing up with:

10:23:33] # ttm_device_init_pools: ASSERTION FAILED at drivers/gpu/drm/ttm/tests/ttm_device_test.c:178
[10:23:33] Expected !list_lru_count(&pt.pages) to be false, but is true
[10:23:33] [FAILED] DMA allocations, DMA32 required
[10:23:33] [PASSED] No DMA allocations, DMA32 required
[10:23:33] # ttm_device_init_pools: ASSERTION FAILED at drivers/gpu/drm/ttm/tests/ttm_device_test.c:178
[10:23:33] Expected !list_lru_count(&pt.pages) to be false, but is true

Fixes: 444e2a19d7fd ("ttm/pool: port to list_lru. (v2)")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Dave Airlie <airlied@redhat.com>
Reviewed-by: Ryszard Knop <ryszard.knop@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patch.msgid.link/20260409121512.81298-3-matthew.auld@intel.com