While we only use stdin, the chardev is named 'stdio'.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20210602170759.2500248-4-f4bug@amsat.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>