[M] Change in coreboot[main]: mb/google/rauru: Add support for getting storage id

[Yidi Lin (Code Review)]

Attention is currently required from: Hung-Te Lin, Jarried Lin, Yu-Ping Wu.

Yidi Lin has posted comments on this change by Jarried Lin. ( https://review.coreboot.org/c/coreboot/+/85717?usp=email )

Change subject: mb/google/rauru: Add support for getting storage id
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Patch Set 1:

(2 comments)

File src/mainboard/google/rauru/mainboard.c:

https://review.coreboot.org/c/coreboot/+/85717/comment/1b447840_ca291771?usp... :
PS1, Line 60: 	mt6363_init_pmif_arb();
            : 	mt6363_enable_vtref18(true);
            : 	mt6363_set_vtref18_voltage(1800000);
            : 	mt6363_get_vtref18_voltage();
> Move to `romstage`. […]

An alternative is powering on `vtref18` in `storage_id` (since this power rail is board-specific design). But it may take times to ramp up.

File src/mainboard/google/rauru/storage.h:

https://review.coreboot.org/c/coreboot/+/85717/comment/8c7f992d_6e76373e?usp... :
PS1, Line 5: 
```
enum storage_type {
 ....
};
```