target/arm: Merge zcr reginfo

Drop zcr_no_el2_reginfo and merge the 3 registers into one array,
now that ZCR_EL2 can be squashed to RES0 and ZCR_EL3 dropped
while registering.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220506180242.216785-4-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>