cpuidle: kirkwood: Make kirkwood_cpuidle_remove function static
This local symbol is used only in this file.
Fix the following sparse warnings:
drivers/cpuidle/cpuidle-kirkwood.c:73:5: warning: symbol 'kirkwood_cpuidle_remove' was not declared. Should it be static ?
Signed-off-by: Jingoo Han <jg1.han@samsung.com> Acked-by: Jason Cooper <jason@lakedaemon.net> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>