ply-device-manager: Accept new simpledrm/fbdev devices from udev events after timeout

Before the device-timeout elapses verify_add_or_change () blocks new simpledrm and fbdev getting added through udev add events because we really only want native drm devices.

Then when the timeout triggers the list of udev devices existing at that point int time is rescanned and any drm (including simpledrm) and fbdev devices are added (filtering out duplicates).

But what if a simpledrm or fbdev device for some reason only shows up after the timeout? Before this change those would then be ignored for ever.

Add a manager->device_timeout_elapsed check and make verify_add_or_change () accept any drm + fbdev devices after the timeout. Note this addresses a mostly theoretically issue since in practice a simpledrm or fbdev device showing up later is very unlikely.