target/arm: Implement VFP fp16 VMLA, VMLS, VNMLS, VNMLA, VNMUL

target/arm: Implement VFP fp16 VMLA, VMLS, VNMLS, VNMLA, VNMUL

Implement fp16 versions of the VFP VMLA, VMLS, VNMLS, VNMLA, VNMUL
instructions. (These are all the remaining ones which we implement
via do_vfp_3op_[hsd]p().)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200828183354.27913-5-peter.maydell@linaro.org