Expose SPI sio() setting

[ElDonad]

Hello,
I was trying to setup three wires SPI for my application using an ESP32-S3, and it appears that the esp-hal API doesn't expose this setting. Would it be possible to expose this functionality ? I don't think it would be very hard, there could be a helper function akin to Spi::with_sio() that would resemble something like

fun with_sio(self) -> Self{
    let reg_block = self.register_block();
    reg_block.user().modify(|_,w| unsafe {
        w.sio().set_bit();
    }
    self
}

I'm fairly new to ESP and Rust dev and I don't have the means to thoroughly test this PoC currently, so I hope it's not too far from correct...

[bjoernQ]

That would be a useful addition

[ElDonad]

By the way there is not much information about it in the technical manual, but I assume this should only be available for the Half Duplex mode, it wouldn't make sense otherwise. I'll try to get it to work on a ESP32S3 I have, maybe then I can issue a PR...

[MabezDev]

As per the pending PR, this can be done, and if we wanted it could even be added post 1.0.