x86,misc: add additional info on faulting X86 instruction, fetched PC

Print faulting instruction for unmapped address panic in faults.cc
and print extra info about corresponding fetched PC in base.cc.

Change-Id: Id9e15d3e88df2ad6b809fb3cf9f6ae97e9e97e0f
Reviewed-on: https://gem5-review.googlesource.com/6461
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
2 files changed