SH: cpuidle: Add missing parameter for cpuidle_register()

arch/sh/kernel/cpu/shmobile/cpuidle.c: In function 'sh_mobile_setup_cpuidle':
arch/sh/kernel/cpu/shmobile/cpuidle.c:102:2: error: too few arguments to function 'cpuidle_register'
include/linux/cpuidle.h:129:12: note: declared here
arch/sh/kernel/cpu/shmobile/cpuidle.c:94:6: warning: unused variable 'ret' [-Wunused-variable]

Add the missing parameter, and remove the unused variable.

Both introduced by commit b181a3b03f866776211f22390c185c4da1dc45ff ("SH:
cpuidle: use init/exit common routine").

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>