sim: no rule to make sim/ppc/Makefile.in

Seen with --enable-maintainer-mode.
make[3]: *** No rule to make target '.../sim/ppc/Makefile.in', needed
by 'ppc/stamp-pk'.  Stop.

	* sim/ppc/local.mk (stamp-pk): Depend on local.mk not
	Makefile.in.
	* Makefile.in: Regenerate.

Approved-By: Tom Tromey <tom@tromey.com>