feat(qemu): implement firmware handoff on qemu

Implement firmware handoff from BL2 to BL33 on qemu platform
compliant to Firmware handoff specification v0.9.

Change-Id: Id8d5206a71ef6ec97cf3c97995de328ebf0600cc
Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
diff --git a/plat/qemu/common/qemu_image_load.c b/plat/qemu/common/qemu_image_load.c
index 9970d1d..2b02a67 100644
--- a/plat/qemu/common/qemu_image_load.c
+++ b/plat/qemu/common/qemu_image_load.c
@@ -1,11 +1,13 @@
 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2023, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
 #include <common/desc_image_load.h>
 
+#include "qemu_private.h"
+
 /*******************************************************************************
  * This function is a wrapper of a common function which flushes the data
  * structures so that they are visible in memory for the next BL image.
@@ -13,6 +15,7 @@
 void plat_flush_next_bl_params(void)
 {
 	flush_bl_params_desc();
+	qemu_bl2_sync_transfer_list();
 }
 
 /*******************************************************************************