m68k: fix crufty 68000 and 68360 intro comments

Quite a few of the non-mmu specific support files have a pathname in the
title comments of the file. These files have moved around a bit over the
years, and most are no longer accurate. Remove the pathname and fix the
comments to include at least a short description of the files contents.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>