target/i386/tcg: unify MOVBE and BSWAP generators APX allows register-to-register MOVBE, which is normally done by BSWAP (except 16-bit is also allowed). Modify gen_MOVBE to also handle BSWAP. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>