Fix m32r-elf sim, default hardware to off.

Fix m32r-elf sim, default hardware to off.

The situation here is similar to that of the other nearby (previous)
sims fixed; it fails at the dv_sockser_install declaration in
sim/m32r/tconfig.in.  But, as opposed to e.g. frv, this *does* have a
definition of UART_INCHAR_ADDR et al.  It's somewhat tempting to keep
sim-hardware enabled here but, I'm disabling it for the same reasons
as for frv.  Unsurprisingly (as m32r seems to be the template), the
same confusing lines are in sim/m32r/Makefile.in as in
sim/frv/Makefile.in at that time, deleted in 73e76d20.  Again, commit
73e76d20 (for m32r as well as for frv) attempted to move the
non-existing dv-sockser.o use to $(m32r_extra_objs) but missed that
AC_SUBST would only affect @m32r_extra_objs@ and not
$(m32r_extra_objs) per se so nothing happened.  As for frv, I'm
removing the $(m32r_extra_objs) too, to avoid confusion.  Make
check-sim for m32r-elf shows no regressions (5 failures; 100 expected
passes) compared to bf3d9781ec049 (before the recent config.in regen,
after sim-hardware mostly-enabled) and eed23bb4a1 (before the
sim-hardware mostly-enabled; 2013-03-23).

sim/m32r:
	* configure.ac: Default simulator hardware to off again.  Remove
	dead m32r_extra_objs substitution.
	* configure: Regenerate.
	* Makefile.in: Remove unused frv_extra_objs.