avr: move timing control from ma_light to sk6812.

This allows for better control over the LED strip. We can now trigger the
LED strip externally (e.g. by setting a new RGBW value).

avr/devices/all/modules_100ms.asm

@@ -102,6 +102,10 @@ modulesOnEvery100ms:
   bigcall XPT2046_Every100ms
 #endif
 
+#ifdef MODULES_SK6812
+  bigcall SK6812_Every100ms
+#endif
+
   ret
 ; @end