soc: qcom: spm: Use const and __initconst for qcom_cpuidle_ops

The qcom_cpuidle_ops structures is not over-written, so add "const"
qualifier and replace __initdata with __initconst.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Andy Gross <andy.gross@linaro.org>