ws2812: add support for the ESP32-C3 processor

This adds support to the WS2812 for the ESP32-C3 processor
which is a RISC-V processor from Espressif.

Signed-off-by: deadprogram <ron@hybridgroup.com>

ws2812/ws2812_esp32c3.go

@@ -0,0 +1,16 @@
+//go:build esp32c3
+
+package ws2812
+
+import "machine"
+
+// Send a single byte using the WS2812 protocol.
+func (d Device) WriteByte(c byte) error {
+	switch machine.CPUFrequency() {
+	case 160_000_000: // 160MHz
+		d.writeByte160(c)
+		return nil
+	default:
+		return errUnknownClockSpeed
+	}
+}