intel: fix -Wunused-(but-set-)variable warnings
diff --git a/icd/intel/layout.h b/icd/intel/layout.h
index f081e37..fc86155 100644
--- a/icd/intel/layout.h
+++ b/icd/intel/layout.h
@@ -165,7 +165,8 @@
 intel_layout_mem_to_raw(const struct intel_layout *layout,
                         unsigned mem_x, unsigned mem_y)
 {
-   unsigned tile_w, tile_h;
+   unsigned tile_w U_ASSERT_ONLY;
+   unsigned tile_h;
 
    switch (layout->tiling) {
    case INTEL_TILING_NONE: