ACPI / processor: Get power info before updating the C-states

acpi_processor_get_power_info() has to be called before
acpi_processor_setup_cpuidle_states() to have the latest
information available. This fixes the missing C-state information
after AC-->DC transition.

Signed-off-by: Thomas Schlichter <thomas.schlichter@web.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>