intel: implement cmd_draw_meta()

It emits the necessary hardware states for a meta op.  Copying with
depth/stencil or multisample source is not supported yet.  Clearing
depth/stencil destination is also unsupported.
diff --git a/icd/intel/cmd.h b/icd/intel/cmd.h
index 04551e0..123c77f 100644
--- a/icd/intel/cmd.h
+++ b/icd/intel/cmd.h
@@ -45,6 +45,7 @@
 
 struct intel_cmd_item;
 struct intel_cmd_reloc;
+struct intel_cmd_meta;
 
 /*
  * We know what workarounds are needed for intel_pipeline.  These are mostly
@@ -142,6 +143,8 @@
  * the command buffer when possible, and reduce this struct.
  */
 struct intel_cmd_bind {
+    const struct intel_cmd_meta *meta;
+
     struct intel_cmd_shader_cache shader_cache;
 
     struct {