turnip: Fix a compiler warning in release builds of the query code.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6592>
diff --git a/src/freedreno/vulkan/tu_query.c b/src/freedreno/vulkan/tu_query.c
index 2bdc4d3..e8a1a29 100644
--- a/src/freedreno/vulkan/tu_query.c
+++ b/src/freedreno/vulkan/tu_query.c
@@ -158,7 +158,7 @@
       slot_size = sizeof(struct pipeline_stat_query_slot);
       break;
    default:
-      assert(!"Invalid query type");
+      unreachable("Invalid query type");
    }
 
    struct tu_query_pool *pool =