target/arm: Implement SVE2 RSUBHNB, RSUBHNT

target/arm: Implement SVE2 RSUBHNB, RSUBHNT

This completes the section 'SVE2 integer add/subtract narrow high part'

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stephen Long <steplong@quicinc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210525010358.152808-42-richard.henderson@linaro.org
Message-Id: <20200417162231.10374-5-steplong@quicinc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>