This adds a common helper to compute the effective value of MDCR_EL2.
That is the actual value if EL2 is enabled in the current security
context, or 0 elsewise.
Signed-off-by: Rémi Denis-Courmont <remi.denis.courmont@huawei.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210112104511.36576-5-remi.denis.courmont@huawei.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>