[U-Boot] [RFC] ARM timing code refactoring

[Reinhard Meyer]

Dear Wolfgang Denk,
> Dear Albert ARIBAUD,

With all this half quoting and deleting of important parts,
my original proposal was lost again.

If you really care to look at it, it

1. does not have issues with rollover
2. does not have problems with nested timeouts
3. does 64 bit mul/div calculations only once at the begin of a timeout
4. is easy and straightforward to use
5. needs very few lines of code to implement

Calculating the end time at the begin of a loop is not a problem,
I am not aware of any timeout loops where the timeout value needs to be changed
inside the loop.

Reinhard