Convert the Neon VRINT-with-specified-rounding-mode insns to gvec,
and use this to implement the fp16 versions.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-41-peter.maydell@linaro.org