Fix stm32 SPI examples

examples/stm32f3/src/bin/spi_dma.rs

@@ -8,7 +8,6 @@ use core::str::from_utf8;
 use defmt::*;
 use embassy_executor::Spawner;
 use embassy_stm32::spi::{Config, Spi};
-use embassy_stm32::time::Hertz;
 use heapless::String;
 use {defmt_rtt as _, panic_probe as _};
 
@@ -24,7 +23,6 @@ async fn main(_spawner: Spawner) {
         p.PB4,
         p.DMA1_CH3,
         p.DMA1_CH2,
-        Hertz(1_000_000),
         Config::default(),
     );