[S] Change in coreboot[main]: mb/google/rauru: Configure firmware display for eDP panel

[Yidi Lin (Code Review)]

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

Yidi Lin has posted comments on this change by Jarried Lin. ( https://review.coreboot.org/c/coreboot/+/85952?usp=email )

Change subject: mb/google/rauru: Configure firmware display for eDP panel
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Patch Set 4:

(1 comment)

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

https://review.coreboot.org/c/coreboot/+/85952/comment/984ac950_100b8077?usp... :
PS4, Line 103: mt6373_init_pmif_arb();
             : 		mt6373_enable_vcn33_3(true);
             : 		mt6373_set_vcn33_3_voltage(3300000);
Move those call to a separate function.
```
static void enable_display_power_rail(void)
{
    mt6373_init_pmif_arb();
    mt6373_enable_vcn33_3(true);
    mt6373_set_vcn33_3_voltage(3300000);
}

...

if (display_init_required()) {
    enable_display_power_rail();
    mtk_display_init();
}
```