Calling led_sync every cycle kills performance

[algernon]

As the title says, see keyboardio/Kaleidoscope#113 for the discussion. Short version is that adding the LEDOff effect to a sketch that has a main loop run at 2.2-2.4ms, pushes the duration towards 10ms, usually over it, too.

Perhaps it would be enough to call led_sync fewer times. If I'm not mistaken, calling it every ~16ms would still result in ~60 updates / second (which is plenty), and have a much smaller impact on average loop length.