[S] Change in coreboot[main]: soc/intel/common/gpio: add function to lock GPIO configuration

[Wonkyu Kim (Code Review)]

Attention is currently required from: Bora Guvendik, Cliff Huang, Hannah Williams, Jérémy Compostella, Pranava Y N, Subrata Banik.

Wonkyu Kim has posted comments on this change by Cliff Huang. ( https://review.coreboot.org/c/coreboot/+/84901?usp=email )

Change subject: soc/intel/common/gpio: add function to lock GPIO configuration
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Patch Set 3: Code-Review+1

(1 comment)

File src/soc/intel/common/block/gpio/gpio.c:

https://review.coreboot.org/c/coreboot/+/84901/comment/dd45b336_01013355?usp... :
PS3, Line 485: /* Clear lock for the exception PADs */
> Hi Subrata, This is a TODO to a TODO. […]

I think it's implementation way difference. 
We can lock each pin mux table by using existing _LOCK macro but it may be work if we want to lock some of pin's configuration.
Basic assumption for this change(having exception table for lock) is for locking most of pin configuration for system safety.  And it'll require less change compared to changing entire pin configuration in gpio.c.