faster SPI bus speed

src/radio.rs

@@ -23,7 +23,7 @@ pub struct McuRadio {
 
 impl McuRadio {
     pub fn new() -> anyhow::Result<Self> {
-        let spi = Spi::new(Bus::Spi0, SlaveSelect::Ss1, 1_000_000, Mode::Mode0)?;
+        let spi = Spi::new(Bus::Spi0, SlaveSelect::Ss1, 2_000_000, Mode::Mode0)?;
         let reset_pin = Gpio::new()?.get(8)?.into_output_high();
 
         let mut s = Self { reset_pin, spi };