dpms: Add support for DPMSInfoNotify event from DPMS 1.2 (xorgproto)

This allows applications to respond to changes of power level
of a monitor, e.g. an application may stop rendering and related
calculations when the monitor is off.

Related bug: https://bugs.freedesktop.org/57120

Signed-off-by: Alexander Volkov <a.volkov@rusbitech.ru>
4 jobs for dpms in 6 minutes and 47 seconds (queued for 1 second)