Make sure that the PTRACE_... symbols are available for ppc/plt.c.

On a Fedora 12 x86_64 build/host box, this file was complaining about
PTRACE_PEEKTEXT being undefined. Adding in the "ptrace.h" include
fixed it.

Signed-off-by: Anthony Foiani <anthony.foiani@gmail.com>

 # m68k specific configuration file

 # depends on EXPERIMENTAL

 config ARCH_m68k

     select ARCH_SUPPORTS_32

     select ARCH_DEFAULT_32

     select ARCH_DEFAULT_BE

     select ARCH_SUPPORT_CPU

      help

       The m68k architecture