Add support for stm32f4 additional PLL SAI divider

I'm as new to Rust as to Embassy, so sorry if this does not match your coding standards, but at least it works.

embassy-stm32/src/rcc/f247.rs

@@ -200,8 +200,6 @@ pub(crate) unsafe fn init(config: Config) {
     RCC.dckcfgr().modify(|w| w.set_pllsaidivq(config.pllsai_divdivq));
     pllsai.q = Some(unwrap!(pllsai.q) / (1 + config.pllsai_divdivq.to_bits()));
 
-
-    info!("KAPOUE {}",pllsai.q);
     // Configure sysclk
     let sys = match config.sys {
         Sysclk::HSI => unwrap!(hsi),