[M] Change in coreboot[main]: Use common GCD function

[Yidi Lin (Code Review)]

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

Yidi Lin has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/78799?usp=email )

Change subject: Use common GCD function
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Patch Set 5:

(2 comments)

File src/drivers/analogix/anx7625/anx7625.c:

https://review.coreboot.org/c/coreboot/+/78799/comment/ff1bee96_99361f57 :
PS4, Line 157: static void anx7625_reduction_of_a_fraction(unsigned long *_a,
> Can we change the types of a, b, m, n (and others) to `u32`?

Done

File src/northbridge/intel/ironlake/quickpath.c:

https://review.coreboot.org/c/coreboot/+/78799/comment/10a6b59f_0b982624 :
PS4, Line 20: static unsigned int lcm(unsigned int a, unsigned int b)
> u32

Done