Add a note about a bug in how sio manages its softc.  This was discovered by Dorr H. Clark.  I'm not at all sure how to fix it, but wanted to document it at the very least...
Add a note about a bug in how sio manages its softc.  This was
discovered by Dorr H. Clark.  I'm not at all sure how to fix it, but
wanted to document it at the very least...

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