target/arm: Implement FEAT_HAFDBS, dirty bit portion

Perform the atomic update for hardware management of the dirty bit.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20221024051851.3074715-14-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2 files changed