Change in coreboot[master]: mb/adlrvp: Add hook function to return EC in RW status

[Hsuan-ting Chen (Code Review)]

Attention is currently required from: Bora Guvendik, Anil Kumar K, Selma Bensaid, Tim Wawrzynczak, Bernardo Perez Priego.
Hsuan-ting Chen has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/58099 )

Change subject: mb/adlrvp: Add hook function to return EC in RW status
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Patch Set 4:

(1 comment)

File src/mainboard/intel/adlrvp/chromeos.c:

https://review.coreboot.org/c/coreboot/+/58099/comment/93358ca3_bad55eda 
PS4, Line 50: int get_ec_is_trusted(void)
            : {
            : 	/* EC is trusted if not in RW. */
            : 	return !gpio_get(GPIO_EC_IN_RW);
            : }
There is nothing left in depthcharge to handle that "EC in RW" gpios.
(removed at: https://chromium-review.googlesource.com/c/chromiumos/platform/depthcharge/+...)

Now, the equivalent logic is moved to coreboot and handled by this function.

So I think we should guard this function as well. (It will use the default __weak function in src/third_party/coreboot/src/security/vboot/bootmode.c instead, which always returns false)