Arm platforms: Fix type mismatch for arm_pm_idle_states

This also gets rid of MISRA violations for Rule 8.3 and 8.4.

Change-Id: I45bba011b16f90953dd4b260fcd58381f978eedc
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
2 files changed