Rip out the (old) copy of sys/mtio.h that passed for documentation
of the tape ioctls - if we're going to be that lame, just tell 'em
to UTSL. Some other brave soul will have to do the documentation of
each specific ioctl beyond the comments in that file.
Write text about generic UNIX tape handling, which sucks and probably
always will.
This puts PR#5698 to bed.
kleink