M_TTYS -> M_DEVBUF.  M_TTYS is documented to be for "tty data structures" but since tty structs aren't malloced it is actually mainly for tty-level (clist) buffers.  It was slightly misused here for com structs, and the previous commit completely misused it for device buffers.
M_TTYS -> M_DEVBUF.  M_TTYS is documented to be for "tty data
structures" but since tty structs aren't malloced it is actually
mainly for tty-level (clist) buffers.  It was slightly misused
here for com structs, and the previous commit completely misused
it for device buffers.

Fixed some bugs in nearby pccard code:
- memory leak when pccards go away (broken in previous commit).
- bogus bzeroing of the com struct before freeing it.
- style bugs.

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