target/arm: Add ID_AA64ISAR2_EL1

target/arm: Add ID_AA64ISAR2_EL1

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230829232335.965414-3-richard.henderson@linaro.org
[PMM: drop the HVF part of the patch and just comment that
 we need to do something when the register appears in that API]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>