module/power_domain: Send system suspend notification
When the last core is going off, send a system suspend notification to the platform specific sleep module where it will handle the final stages of the suspend itself, or we can configure the power domain to do a complete system suspend inside the power domain instead of sending notification.
Signed-off-by: mahmoh02 mahmoud.magdy@arm.com Change-Id: I6adcb1b98225c43083bafb623cb6745521fb4e84