Change in coreboot[master]: soc/intel/common: Add `struct gpio_pad_table` and helpers

[Angel Pons (Code Review)]

Attention is currently required from: Furquan Shaikh, Subrata Banik, Michael Niewöhner, Patrick Rudolph.
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/50176 )

Change subject: soc/intel/common: Add `struct gpio_pad_table` and helpers
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Patch Set 1:

(1 comment)

File src/soc/intel/common/block/include/intelblocks/gpio.h:

https://review.coreboot.org/c/coreboot/+/50176/comment/c24be320_ed7964fb 
PS1, Line 75: 	const struct pad_config *padcfg;
            : 	size_t length;
            :
> Hmmm, good point. […]

I'll keep this as-is for now. One can prefix the struct type with const, if need be.