Remove common clock types

Different STM32 RCC peripherals have different capabilities and register
values. Define types for each RCC types inside each module to ensure
full range of capabilities for each family can be used

embassy-stm32/src/rcc/mod.rs

@@ -3,7 +3,6 @@
 use crate::peripherals;
 use crate::time::Hertz;
 use core::mem::MaybeUninit;
-mod types;
 
 #[derive(Clone, Copy)]
 pub struct Clocks {