Extend the message in UPDATING on the sio(4) -> uart(4) change.
Extend the message in UPDATING on the sio(4) -> uart(4) change.

It turns out I forgot to mention that people really need to make sure
their hints are up to date if they are updating a system through the
serial console.

Requested by:	gavin
Reviewed by:	gavin

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase