[S] Change in coreboot[main]: arch/arm64/arch_timer: Fix possible overflow in multiplication

[Yidi Lin (Code Review)]

Attention is currently required from: Arthur Heymans, Julius Werner, Paul Menzel, Yu-Ping Wu.

Yidi Lin has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/78800?usp=email )

Change subject: arch/arm64/arch_timer: Fix possible overflow in multiplication
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Patch Set 3:

(3 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/78800/comment/7db06ffe_abd141fc :
PS2, Line 9: The value from raw_read_cntfrq_el0() could be large enough to cause
           : overflow when multiplied by 1000000. To prevent this, both 1000000 and
           : tfreq can be reduced by dividing them by their GCD.
> I think it's worth adding this as a comment to the code.

Done

File src/arch/arm64/arch_timer.c:

https://review.coreboot.org/c/coreboot/+/78800/comment/8d01b460_535d41a3 :
PS2, Line 16: 		assert(tfreq > 0)
> Missing semicolon (also, this is probably not necessary, you'll get a pretty obvious division-by-zer […]

Removed.

https://review.coreboot.org/c/coreboot/+/78800/comment/aaec0543_7ad7b56d :
PS2, Line 18: 		div = gcd(mult, tfreq);
> nit: depending on the GCD implementation you'll probably want to write it as `gcd(tfreq, mult)` to h […]

Done