intel: declare intel_dev in layout.h
diff --git a/icd/intel/layout.h b/icd/intel/layout.h
index 527912d..63b6a53 100644
--- a/icd/intel/layout.h
+++ b/icd/intel/layout.h
@@ -33,6 +33,8 @@
 
 #define INTEL_LAYOUT_MAX_LEVELS 16
 
+struct intel_dev;
+
 enum intel_layout_walk_type {
    /*
     * Array layers of an LOD are packed together vertically.  This maps to