ac: add gs_{prim,invocation}_id to the abi

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

src/amd/common/ac_shader_abi.h

@@ -42,6 +42,8 @@ struct ac_shader_abi {
 	LLVMValueRef draw_id;
 	LLVMValueRef vertex_id;
 	LLVMValueRef instance_id;
+	LLVMValueRef gs_prim_id;
+	LLVMValueRef gs_invocation_id;
 	LLVMValueRef frag_pos[4];
 	LLVMValueRef front_face;
 	LLVMValueRef ancillary;