Enable FEAT_DIT for the "max" 32-bit CPU.

Signed-off-by: Rebecca Cran <rebecca@nuviainc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210208065700.19454-5-rebecca@nuviainc.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>