ACPI: processor: idle: Fix memory leak when register cpuidle device failed

ACPI: processor: idle: Fix memory leak when register cpuidle device failed

The cpuidle device's memory is leaked when cpuidle device registration
fails in acpi_processor_power_init().  Free it as appropriate.

Fixes: 3d339dcbb56d ("cpuidle / ACPI : move cpuidle_device field out of the acpi_processor_power structure")
Signed-off-by: Huisong Li <lihuisong@huawei.com>
Link: https://patch.msgid.link/20250728070612.1260859-2-lihuisong@huawei.com
[ rjw: Changed the order of the new statements, added empty line after if () ]
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>