cpuidle: arm_big_little: Initialise earlier by using device_initcall

Using late_initcall is too late for IKS.

Requested-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
diff --git a/drivers/cpuidle/arm_big_little.c b/drivers/cpuidle/arm_big_little.c
index a430800..e537889 100644
--- a/drivers/cpuidle/arm_big_little.c
+++ b/drivers/cpuidle/arm_big_little.c
@@ -180,4 +180,4 @@
 	return 0;
 }
 
-late_initcall(bl_idle_init);
+device_initcall(bl_idle_init);