embassy-stm32: Simplify time

- Remove unused `MilliSeconds`, `MicroSeconds`, and `NanoSeconds` types
- Remove `Bps`, `KiloHertz`, and `MegaHertz` types that were only used
for converting to `Hertz`
- Replace all instances of `impl Into<Hertz>` with `Hertz`
- Add `hz`, `khz`, and `mhz` methods to `Hertz`, as well as
free function shortcuts
- Remove `U32Ext` extension trait

embassy-stm32/src/rcc/wl.rs

@@ -1,6 +1,6 @@
 use crate::pac::{FLASH, RCC};
 use crate::rcc::{set_freqs, Clocks};
-use crate::time::{Hertz, U32Ext};
+use crate::time::Hertz;
 
 /// Most of clock setup is copied from stm32l0xx-hal, and adopted to the generated PAC,
 /// and with the addition of the init function to configure a system clock.
@@ -320,14 +320,14 @@ pub(crate) unsafe fn init(config: Config) {
     while FLASH.acr().read().latency() != ws {}
 
     set_freqs(Clocks {
-        sys: sys_clk.hz(),
-        ahb1: ahb_freq.hz(),
-        ahb2: ahb_freq.hz(),
-        ahb3: shd_ahb_freq.hz(),
-        apb1: apb1_freq.hz(),
-        apb2: apb2_freq.hz(),
-        apb3: apb3_freq.hz(),
-        apb1_tim: apb1_tim_freq.hz(),
-        apb2_tim: apb2_tim_freq.hz(),
+        sys: Hertz(sys_clk),
+        ahb1: Hertz(ahb_freq),
+        ahb2: Hertz(ahb_freq),
+        ahb3: Hertz(shd_ahb_freq),
+        apb1: Hertz(apb1_freq),
+        apb2: Hertz(apb2_freq),
+        apb3: Hertz(apb3_freq),
+        apb1_tim: Hertz(apb1_tim_freq),
+        apb2_tim: Hertz(apb2_tim_freq),
     });
 }