standalone.c and the VAX xm.h files

[Mark Kettenis]

Looking at the VAX xm.h files I noticed some strange defenitions in
xm-vax.h.  There's a comment in there that says:

/* Interface definitions for kernel debugger KDB.  */

These definitions are used in standalone.c, which AFAICT isn't hooked
up to the build at all.  I suppose this stuff was some sort of
in-kernel debugger, but it must have been unused and broken for years
now.  I propose to whack it.  Objections?

Mark