[cmucl-imp] Remvoing hppa-assem.s

[Raymond Toy]

I don't know why hppa-assem.s is checked in, but it confuses git on a
case-insenstive file system like HPFS on a Mac.

I'm going to delete this file.  This file is not referenced in any of the
Config files or Makefiles.  I'm guessing it's the preprocessed version of
hppa-assem.S.

(There are probably lots of other files that could be removed, like the
hppa directories, but I'm not going there.)

Ray