target/arm: Rename do_zpzi_ool to gen_gvec_ool_arg_zpzi

Rename the function to match gen_gvec_ool_arg_zpz,
and move to be adjacent.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220527181907.189259-24-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>