target/arm: Enable FEAT_Debugv8p8 for -cpu max

target/arm: Enable FEAT_Debugv8p8 for -cpu max

Enable FEAT_Debugv8p8 for max CPU. This feature is out of scope for QEMU
since it concerns the external debug interface for JTAG, but is
mandatory in Armv8.8 implementations, hence it is reported as supported
in the ID registers.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240624180915.4528-4-gustavo.romero@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>