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/Kconfig b/arch/Kconfig
index b396263..eab89f2 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -135,6 +135,7 @@
 	select BZIP2
 	select CMD_POWEROFF
 	select DM
+	select DM_FUZZING_ENGINE
 	select DM_GPIO
 	select DM_I2C
 	select DM_KEYBOARD
@@ -170,6 +171,7 @@
 	imply CRC32_VERIFY
 	imply FAT_WRITE
 	imply FIRMWARE
+	imply FUZZING_ENGINE_SANDBOX
 	imply HASH_VERIFY
 	imply LZMA
 	imply TEE