Now, we have two ways to notify guest about power managment
event:
- ioc on MRB platforms
- ACPI power button on other platforms
And we hardcode which one is used now.
In coming change, we will add UART based guest notify method.
We add dm command option to select which method will be used
when launch UOS.
Tracked-On: #3564
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Reviewed-by: Yuan Liu <yuan1.liu@intel.com>
Acked-by: Wang Yu <yu1.wang@intel.com>