plat/arm: Mark arm platform initialization functions

Mark the initialization functions found in the BL31 boot sequence
as __init so they can be reclaimed when no longer needed.

Change-Id: I687a89346419c7710ef5097feaa325d83c527697
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
diff --git a/plat/arm/common/arm_console.c b/plat/arm/common/arm_console.c
index 6c8587f..bd3dca1 100644
--- a/plat/arm/common/arm_console.c
+++ b/plat/arm/common/arm_console.c
@@ -19,7 +19,7 @@
 #endif
 
 /* Initialize the console to provide early debug support */
-void arm_console_boot_init(void)
+void __init arm_console_boot_init(void)
 {
 #if MULTI_CONSOLE_API
 	int rc = console_pl011_register(PLAT_ARM_BOOT_UART_BASE,