evdev: Fix a compile warning

device_type_str is only used inside a CLUTTER_NOTE, which evaluate
to nothing when CLUTTER_ENABLE_DEBUG is off.
egl: Add a way to pause the ClutterMasterClock

When VT switched away, we need to pause the ClutterMasterClock,
stop processing events, and stop trying to flip.

https://bugzilla.gnome.org/show_bug.cgi?id=730215