intel: fix -Wunused-(but-set-)variable warnings
diff --git a/icd/intel/cmd_pipeline.c b/icd/intel/cmd_pipeline.c
index fd70805..42ac706 100644
--- a/icd/intel/cmd_pipeline.c
+++ b/icd/intel/cmd_pipeline.c
@@ -3055,7 +3055,7 @@
                      uint32_t vertex_base)
 {
     const struct intel_pipeline *p = cmd->bind.pipeline.graphics;
-    const uint32_t surface_writer_used =
+    const uint32_t surface_writer_used U_ASSERT_ONLY =
         cmd->writers[INTEL_CMD_WRITER_SURFACE].used;
 
     cmd_adjust_state_base_address(cmd);