In addition to allowing read-only and write-only consoles with --stdin
and --stdout, we now allow bidirectional read/write consoles with FIFO
files. This is e.g. to allow doing RATP over the FIFO based consoles.

Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>