overlays: adau1977-adc: Replace use of i2c label

The label 'i2c' is no longer created by the firmware - i2c_arm or
i2c1 should be used instead. Replace the last occurrence of &i2c with
&i2c1.

Signed-off-by: Phil Elwell <[email protected]>

Author: pelwell

arch/arm/boot/dts/overlays/adau1977-adc-overlay.dts

@@ -6,7 +6,7 @@
 	compatible = "brcm,bcm2835";
 
 	fragment@0 {
-        	target = <&i2c>;
+		target = <&i2c1>;
 
 		__overlay__ {
 			#address-cells = <1>;