autoport: Add missing command to readme

The readme.md file was missing the instruction to also compile superiotool,
because autoport errors out without a working version of it.

Change-Id: Ic426b7312f68d59e2e0503d61da694adc9d4fb3f
Signed-off-by: Christoph Pomaska <cp_public@gmx.de>
Reviewed-on: https://review.coreboot.org/23282
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>

util/autoport/readme.md

@@ -28,6 +28,8 @@ This will allow autoport to detect as much as possible
 		make
 		cd ../inteltool
 		make
+		cd ../superiotool
+		make
 		cd ../autoport
 		go build
 		sudo ./autoport --input_log=logs --make_logs --coreboot_dir=../..