sim: m32r: migrate from WITH_DEVICES to WITH_HW

sim: m32r: migrate from WITH_DEVICES to WITH_HW

The m32r port was using the device framework to handle two devices: the
cache and uart registers.  Both can be implemented in the newer hardware
framework instead which allows us to drop the device logic entirely, as
well as delete the tconfig.h file.

While creating the new uart device model, I also added support for using
stdin to read/write data rather than only supporting sockets.

This has been lightly tested as there doesn't appear to be test coverage
for the code already.  If anyone still cares about this port, then they
should (hopefully) file bug reports.