sandbox: Implement fuzzing engine driver

Add a fuzzing engine driver for the sandbox to take inputs from
libfuzzer and expose them to the fuzz tests.

Signed-off-by: Andrew Scull <ascull@google.com>
diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index e068d0c..0194b9b 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -92,6 +92,10 @@
 		};
 	};
 
+	fuzzing-engine {
+		compatible = "sandbox,fuzzing-engine";
+	};
+
 	reboot-mode0 {
 		compatible = "reboot-mode-gpio";
 		gpios = <&gpio_c 0 GPIO_ACTIVE_HIGH>, <&gpio_c 1 GPIO_ACTIVE_HIGH>;