m68k: merge the mmu and non-mmu versions of ptrace.c

Most of the code in the non-mmu ptrace_no.c file is the same as the mmu
version ptrace_mm.c. So merge them back into a single file.

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