overlays: Make the i2c-gpio overlay safe again

Like many overlays, the i2c-gpio overlay goes to efforts to avoid
generating warnings about #address-cells and #size-cells not
being defined, which it does by defining them. Unfortunately this
is fatal if they don't match what the system requires, and the
recent switch to #size-cells = 2 on 2711 made i2c-gpio very
dangerous.

In the absence of the knowledge of a clean way to fix this, just delete
the declarations and suffer the warnings.

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

arch/arm/boot/dts/overlays/i2c-gpio-overlay.dts

@@ -9,9 +9,6 @@
 		target-path = "/";
 
 		__overlay__ {
-			#address-cells = <1>;
-			#size-cells = <0>;
-
 			i2c_gpio: i2c@0 {
 				reg = <0xffffffff>;
 				compatible = "i2c-gpio";