hvf: arm: Handle unknown ID registers as RES0

hvf: arm: Handle unknown ID registers as RES0

Recent Linux versions added support to read ID_AA64ISAR2_EL1. On M1,
those reads trap into QEMU which handles them as faults.

However, AArch64 ID registers should always read as RES0. Let's
handle them accordingly.

This fixes booting Linux 5.17 guests.

Cc: qemu-stable@nongnu.org
Reported-by: Ivan Babrou <ivan@cloudflare.com>
Signed-off-by: Alexander Graf <agraf@csgraf.de>
Message-id: 20220209124135.69183-2-agraf@csgraf.de
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>