evdev: Use microsecond granularity for internal timestamps
evdev: Use microsecond granularity for internal timestamps

It's what libinput uses internally, and it'll be exposed in a later
patch.

https://bugzilla.gnome.org/show_bug.cgi?id=752752

GNOME/clutter,GNOME/clutter,GNOME/clutter,GNOME/clutter,GNOME/clutter