Revert "cpuidle/arm64: Remove redundant cpuidle_idle_call()"

This reverts commit c31ed3c0.

The prerequisite changes to call cpuidle_idle_call() from an
architecture-independent location are not present in this kernel
tree. As a result, removing the call from arm64 code results in
cpuidle_idle_call() never being invoked at all, and prevents
entry into any low power idle states.

Change-Id: Ia94b369b9b139ed3bc1d0260609665f6fe47b0fe
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>