stm32f1: Store adc clock rate in Clocks struct

embassy-stm32/src/rcc/f1/mod.rs

@@ -202,6 +202,7 @@ impl<'d> Rcc<'d> {
             apb1_tim: Hertz(pclk1 * timer_mul1),
             apb2_tim: Hertz(pclk2 * timer_mul2),
             ahb: Hertz(hclk),
+            adc: Hertz(adcclk),
         }
     }
 }

embassy-stm32/src/rcc/mod.rs

@@ -46,6 +46,9 @@ pub struct Clocks {
 
     #[cfg(rcc_f4)]
     pub pll48: Option<Hertz>,
+
+    #[cfg(rcc_f1)]
+    pub adc: Hertz,
 }
 
 /// Frozen clock frequencies