plat/hikey: boot memory layout to dedicated file

Boot memory layout is specific for a platform, but should not be
mixed up with other platform specific attributes. A separate file is
much cleaner and better to compare with other platforms. Take a look
at plat/poplar where it is done the same way.

Moved hikey_def.h to system include folder and moved includes from
hikey_def.h to more general platform_def.h.

Signed-off-by: Michael Brandl <git@fineon.pw>
diff --git a/plat/hisilicon/hikey/hikey_pm.c b/plat/hisilicon/hikey/hikey_pm.c
index d4dd683..3128a3d 100644
--- a/plat/hisilicon/hikey/hikey_pm.c
+++ b/plat/hisilicon/hikey/hikey_pm.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -10,6 +10,7 @@
 #include <debug.h>
 #include <gicv2.h>
 #include <hi6220.h>
+#include <hikey_def.h>
 #include <hisi_ipc.h>
 #include <hisi_pwrc.h>
 #include <hisi_sram_map.h>
@@ -17,8 +18,6 @@
 #include <psci.h>
 #include <sp804_delay_timer.h>
 
-#include "hikey_def.h"
-
 #define CORE_PWR_STATE(state) \
 	((state)->pwr_domain_state[MPIDR_AFFLVL0])
 #define CLUSTER_PWR_STATE(state) \