sh: Revert the location change of auto-generated asm/machtypes.h

sh: Revert the location change of auto-generated asm/machtypes.h

This ended up causing build breakage on O= builds, as reported by Adrian:

<--  snip  -->

...
  CC      init/main.o
In file included from /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/sh/include/asm/irq.h:4,
                 from /home/bunk/linux/kernel-2.6/git/linux-2.6/include/linux/irq.h:23,
                 from /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/sh/include/asm/hardirq.h:5,
                 from /home/bunk/linux/kernel-2.6/git/linux-2.6/include/linux/hardirq.h:7,
                 from /home/bunk/linux/kernel-2.6/git/linux-2.6/include/asm-generic/local.h:5,
                 from /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/sh/include/asm/local.h:4,
                 from /home/bunk/linux/kernel-2.6/git/linux-2.6/include/linux/module.h:19,
                 from /home/bunk/linux/kernel-2.6/git/linux-2.6/init/main.c:13:
/home/bunk/linux/kernel-2.6/git/linux-2.6/arch/sh/include/asm/machvec.h:15:27:
error: asm/machtypes.h: No such file or directory
make[2]: *** [init/main.o] Error 1

<--  snip  -->

So we simply move machtypes.h back to its original place. asm-offsets.h is
still generated there regardless, until such a time that we find a better place
to stash auto-generated files.

Reported-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>