Do not print the entire ExtMachInst when disassembling an Unknown Instruction. Change-Id: Icd5908ec0fa430090165b2426372bdeb43c2a155 Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/10062 Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>