power: policy: recover deep sleep states from residency policy.

Commit c248cdf1 remove deep sleep states
from residency policy based on SoC loses context in deep sleep states to
avoid a "forever timeout" power-off the whole system. It's right if deep
sleep means power off whole system only.

One of deep sleep states is that most power domains are shut off, but
except a few that retain just enough logic to allow the CPU to resume
from the same point of execution where it went to sleep. This is well
documented and implementations also have same behavior.

For another deep sleep state, system off, sys_pm_ctrl_disable_state can
prevent system off unexpectedly from being entered on long timeout. And
sys_pm_force_power_state can help power off whole system.

This reverts commit c248cdf1.

Signed-off-by: Wentong Wu <wentong.wu@intel.com>