Shutdown immeaditly on ACPI Power Button events (#1896) (#1898)

For phyiscal hardware the default Power Button action has been disabled
to avoid accidentally power down the machine.

However, for virtual machine this method is often used to shutdown the
virtual machine gracefully. Use the regular power settings for virtual
machines.

buildroot-external/board/pc/ova/rootfs-overlay/etc/systemd/logind.conf

@@ -0,0 +1,45 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it under the
+#  terms of the GNU Lesser General Public License as published by the Free
+#  Software Foundation; either version 2.1 of the License, or (at your option)
+#  any later version.
+#
+# Entries in this file show the compile time defaults. Local configuration
+# should be created by either modifying this file, or by creating "drop-ins" in
+# the logind.conf.d/ subdirectory. The latter is generally recommended.
+# Defaults can be restored by simply deleting this file and all drop-ins.
+#
+# Use 'systemd-analyze cat-config systemd/logind.conf' to display the full config.
+#
+# See logind.conf(5) for details.
+
+[Login]
+#NAutoVTs=6
+#ReserveVT=6
+#KillUserProcesses=yes
+#KillOnlyUsers=
+#KillExcludeUsers=root
+#InhibitDelayMaxSec=5
+#UserStopDelaySec=10
+#HandlePowerKey=poweroff
+#HandleSuspendKey=suspend
+#HandleHibernateKey=hibernate
+#HandleLidSwitch=suspend
+#HandleLidSwitchExternalPower=suspend
+#HandleLidSwitchDocked=ignore
+#HandleRebootKey=reboot
+#HandleRebootKeyLongPress=poweroff
+#PowerKeyIgnoreInhibited=no
+#SuspendKeyIgnoreInhibited=no
+#HibernateKeyIgnoreInhibited=no
+#LidSwitchIgnoreInhibited=yes
+#RebootKeyIgnoreInhibited=no
+#HoldoffTimeoutSec=30s
+#IdleAction=ignore
+#IdleActionSec=30min
+#RuntimeDirectorySize=10%
+#RuntimeDirectoryInodesMax=400k
+#RemoveIPC=yes
+#InhibitorsMax=8192
+#SessionsMax=8192