Mark BL31 initialization functions

Mark the initialization functions in BL31, such as context management,
EHF, RAS and PSCI as __init so that they can be reclaimed by the
platform when no longer needed

Change-Id: I7446aeee3dde8950b0f410cb766b7a2312c20130
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
diff --git a/common/runtime_svc.c b/common/runtime_svc.c
index ad564f5..03f7f7e 100644
--- a/common/runtime_svc.c
+++ b/common/runtime_svc.c
@@ -93,7 +93,7 @@
  * The unique oen is used as an index into the 'rt_svc_descs_indices' array.
  * The index of the runtime service descriptor is stored at this index.
  ******************************************************************************/
-void runtime_svc_init(void)
+void __init runtime_svc_init(void)
 {
 	int rc = 0;
 	unsigned int index, start_idx, end_idx;