target/arm: Define new fp_status_f16_a32 and fp_status_f16_a64

target/arm: Define new fp_status_f16_a32 and fp_status_f16_a64

As the first part of splitting the existing fp_status_f16
into separate float_status fields for AArch32 and AArch64
(so that we can make FEAT_AFP control bits apply only
for AArch64), define the two new fp_status_f16_a32 and
fp_status_f16_a64 fields, but don't use them yet.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250124162836.2332150-14-peter.maydell@linaro.org