Implement improved Delay, covering full u32 range

[jamesmunns]

Based on @gbip's impl in https://github.com/therealprof/stm32f4xx-hal

[TeXitoi]

All these copy and pasted delay implementations seems wrong to me. I think this should be addressed in embedded_hal, providing a way to wrap any timer in such a delay function.

[jamesmunns]

I generally agree with you, the issue up to now was the different ways that the main sysclock is exposed in the different HALs.

That being said, I think rust-embedded/embedded-hal#103 is a move in the right direction.

[wez]

Thanks; tested this with the blinky example for metro m0 using a 1s interval and it no longer faults like the old impl used to :-p