Service VM may write 0x6 to port 0xcf9 to trigger a warm reset, but
current hypervisor always performs a cold reset by writing 0xE to CF9.
Hypervisor should reboot the system in the same mode as Service VM
specified. Specific OS features (like linux pstore) requires warm
reset to keep data across reboot.
The behavior of hv console's reboot command (cold reset) remains
unchanged.
Tracked-On: #8539
Signed-off-by: Jiaqing Zhao <jiaqing.zhao@linux.intel.com>
Reviewed-by: Junjie Mao <junjie.mao@intel.com>