target/arm: Implement MVE VQDMULH and VQRDMULH (scalar)

Implement the MVE VQDMULH and VQRDMULH scalar insns, which multiply
elements by the scalar, double, possibly round, take the high half
and saturate.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-29-peter.maydell@linaro.org
4 files changed