all: prepare for CGo changes in TinyGo

For details, see: https://github.com/tinygo-org/tinygo/pull/3927
This change just means we need to be more careful to use the right type,
now that types like C.uint32_t don't match to the Go equivalent (like
uint32).

ws2812/ws2812_avr.go

@@ -60,7 +60,7 @@ func (d Device) WriteByte(c byte) error {
 
 	switch machine.CPUFrequency() {
 	case 16e6: // 16MHz
-		C.ws2812_writeByte16(C.char(c), (*uint8)(unsafe.Pointer(port)), maskSet, maskClear)
+		C.ws2812_writeByte16(C.char(c), (*C.uint8_t)(unsafe.Pointer(port)), C.uint8_t(maskSet), C.uint8_t(maskClear))
 		interrupt.Restore(mask)
 		return nil
 	default: