Eliminate pmax/tc/tc.h. Use dev/tc headers for pmax port. Change pmax TC
autoconfig tables to use structs (mostly) compatible with dev/tc/tcvar.h.
Move TC console search to tc.c.
Update TURBOChannel and ioasic interrupt-establish routines to pass on their
device argument as a "void *", since that's how all the pmax interrupt handlers
are declared.
turhsturbochannel machines. Lifted wholesale from cgd's Alpha
turbochannel code, with changes that reflect the slightly different
bus topology and `slot' numbering on Decstations.