dev: Added new LupIO-TTY device

This device is notfied when data is available from the terminal
(e.g. from keyboard input) in order to receive characters. It also
transmits characters to the terminal to be displayed.

The following are the specifications regarding the LupIO-TTY:
https://gitlab.com/luplab/lupio/lupio-specs/-/blob/main/lupio-tty.md

Change-Id: Icc8294984989cfa422d8ed227da39debfa49ab36
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/53031
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
4 files changed