Q/P modes: Fix inconsistencies on startup

[m-weigand]

The Q and P modes are comprised of

a) the clock speed of the ebc hardware
b) the refresh rate that GNOME is using (this refresh rate is reported as the minitor refresh rate in the corresponding mode lines, but the actual ebc hardware does frame refreshes with only 80 Hz and something lower (I forgot the actual frequencies, this is controlled by the sclk clock speed).

We need to make sure that on start up we either go into Q or P mode. However, it's possible that the clock and refresh states are out of sync at start up. Unfortunately, the extension cannot simply change the screen mode at start up time, as certain things are not set up then (the dbus interface we use to change the display mode).

I think one approach would be a delayed switching: If we detect inconsistencies, trigger a mode change after 5 s when things are set up.