target/arm: Pull calls to disas_sve() and disas_sme() out of legacy decoder

target/arm: Pull calls to disas_sve() and disas_sme() out of legacy decoder

The SVE and SME decode is already done by decodetree.  Pull the calls
to these decoders out of the legacy decoder.  This doesn't change
behaviour because all the patterns in sve.decode and sme.decode
already require the bits that the legacy decoder is decoding to have
the correct values.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230512144106.3608981-4-peter.maydell@linaro.org