boards: frdm_k64f: add arduino i2c node

Add arduino i2c node.

Signed-off-by: Johann Fischer <j.fischer@phytec.de>
diff --git a/boards/arm/frdm_k64f/frdm_k64f.dts b/boards/arm/frdm_k64f/frdm_k64f.dts
index f808a9d..da159f9 100644
--- a/boards/arm/frdm_k64f/frdm_k64f.dts
+++ b/boards/arm/frdm_k64f/frdm_k64f.dts
@@ -121,7 +121,7 @@
 	status = "okay";
 };
 
-&i2c0 {
+arduino_i2c: &i2c0 {
 	status = "okay";
 
 	fxos8700@1d {