Make "set/show cris-version" a zuinteger instead of uinteger.

Make "set/show cris-version" a zuinteger instead of uinteger.

Being a uinteger means you revert back to having GDB decide the
version.  It makes no sense to have an "unlimited" version.

  (gdb) show cris-version
  The current CRIS version is 0.
  (gdb) set cris-version 0
  (gdb) show cris-version
  The current CRIS version is unlimited.
  (gdb)

gdb/
2013-03-26  Pedro Alves  <palves@redhat.com>

	* cris-tdep.c (_initialize_cris_tdep): Make the "set cris-version"
	command zuinteger instead of uinteger.