ACPI / processor: Make acpi_cpu_soft_notify() process CPU FROZEN events

CPU hotplug happens during S2RAM and CPU notify event will be CPU_XXX_FROZEN.
acpi_cpu_soft_notify() ignores to check these events. This also may make
acpi_cpu_soft_notify() fall into sleep during CPU_DYING/STARTING_FROZEN
events which don't allow callbacks to sleep. This patch is to fix it.

Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>