Mark GICV3, CCI and CCN boot time code as init

Mark the GICv3, CCI and CCN code only used in Bl31 initialization
with __init to be reclaimed once no longer needed.

Change-Id: I3d77f36758450d9d1d87ecc60bc1c63fe4082667
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
diff --git a/plat/arm/common/arm_ccn.c b/plat/arm/common/arm_ccn.c
index 84a529f..ddf3286 100644
--- a/plat/arm/common/arm_ccn.c
+++ b/plat/arm/common/arm_ccn.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -34,7 +34,7 @@
 /******************************************************************************
  * Helper function to initialize ARM CCN driver.
  *****************************************************************************/
-void plat_arm_interconnect_init(void)
+void __init plat_arm_interconnect_init(void)
 {
 	ccn_init(&arm_ccn_desc);
 }