boards: update adafruit_feather_nrf52840 dts to add i2c compatible property

This change is needed to correctly generate the devicetree headers
for use in other drivers (ie SSD1306).

Signed-off-by: Jeremy Herbert <[email protected]>

Author: jeremyherbert

boards/arm/adafruit_feather_nrf52840/adafruit_feather_nrf52840.dts

@@ -76,6 +76,7 @@
 };
 
 &i2c0 {
+	compatible = "nordic,nrf-twi";
 	status = "okay";
 	sda-gpios = <&gpio0 12 0>;
 	scl-gpios = <&gpio0 11 0>;