The RTL9300 has a block of GPIOs included in the SoC. Add these to the
devicetree.

This is taken from openwrt[1] the differences are removing the
unnecessary second cell from the interrupt and removing the -controller
from the node name to conform to the dtschema.

[1] - https://git.openwrt.org/?p=openwrt/openwrt.git;a=blob;f=target/linux/realtek/dts/rtl930x.dtsi

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---
 arch/mips/boot/dts/realtek/rtl930x.dtsi | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/mips/boot/dts/realtek/rtl930x.dtsi b/arch/mips/boot/dts/realtek/rtl930x.dtsi
index 77a854034aba..24e262e2dc2a 100644
--- a/arch/mips/boot/dts/realtek/rtl930x.dtsi
+++ b/arch/mips/boot/dts/realtek/rtl930x.dtsi
@@ -156,6 +156,19 @@ watchdog0: watchdog@3260 {
 			interrupts = <5>, <6>;
 		};
 
+		gpio0: gpio@3300 {
+			compatible = "realtek,rtl9300-gpio", "realtek,otto-gpio";
+			reg = <0x3300 0x1c>, <0x3338 0x8>;
+			gpio-controller;
+			#gpio-cells = <2>;
+			ngpios = <24>;
+
+			interrupt-controller;
+			#interrupt-cells = <2>;
+			interrupt-parent = <&intc>;
+			interrupts = <13>;
+		};
+
 		snand: spi@1a400 {
 			compatible = "realtek,rtl9301-snand";
 			reg = <0x1a400 0x44>;
-- 
2.49.0