BCM2708_DT: Use upstreamed GPIO expander driver

The upstreamed driver for the GPIO expander has a different compatible
string. Change the relevant Device Tree files to match.

See: #2704

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

Author: Phil Elwell

arch/arm/boot/dts/bcm2710-rpi-3-b-plus.dts

@@ -84,7 +84,7 @@
 
 &soc {
 	expgpio: expgpio {
-		compatible = "brcm,bcm2835-expgpio";
+		compatible = "raspberrypi,firmware-gpio";
 		gpio-controller;
 		#gpio-cells = <2>;
 		firmware = <&firmware>;

arch/arm/boot/dts/bcm2710-rpi-3-b.dts

@@ -92,7 +92,7 @@
 	};
 
 	expgpio: expgpio {
-		compatible = "brcm,bcm2835-expgpio";
+		compatible = "raspberrypi,firmware-gpio";
 		gpio-controller;
 		#gpio-cells = <2>;
 		firmware = <&firmware>;

arch/arm/boot/dts/bcm2710-rpi-cm3.dts

@@ -52,7 +52,7 @@
 	};
 
 	expgpio: expgpio {
-		compatible = "brcm,bcm2835-expgpio";
+		compatible = "raspberrypi,firmware-gpio";
 		gpio-controller;
 		#gpio-cells = <2>;
 		firmware = <&firmware>;