target/arm: Hoist sve access check through do_sel_z

The check is already done in gen_gvec_ool_zzzp,
which is called by do_sel_z; remove from callers.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220527181907.189259-41-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>