This doesn't completely hide the ISA specific ExtMachInst type inside the ISAs since it still gets applied in arch/generic, but it at least pulls it into the arch directory. Change-Id: Ic2188d59696530d7ecafdff0785d71867182701d Reviewed-on: https://gem5-review.googlesource.com/9403 Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Maintainer: Gabe Black <gabeblack@google.com>