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/lib/extensions/ras/ras_common.c b/lib/extensions/ras/ras_common.c
index 2e65eeb..f39e5f5 100644
--- a/lib/extensions/ras/ras_common.c
+++ b/lib/extensions/ras/ras_common.c
@@ -128,7 +128,7 @@
 	return 0;
 }
 
-void ras_init(void)
+void __init ras_init(void)
 {
 #if ENABLE_ASSERTIONS
 	/* Check RAS interrupts are sorted */