[XL] Change in coreboot[main]: soc/mediatek/mt8196: Add PMIC MT6316 driver

[Yidi Lin (Code Review)]

Attention is currently required from: Hope Wang, 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/+/85630?usp=email )

Change subject: soc/mediatek/mt8196: Add PMIC MT6316 driver
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Patch Set 3:

(3 comments)

File src/soc/mediatek/common/mt6316.c:

https://review.coreboot.org/c/coreboot/+/85630/comment/24fa67cd_c34fb4f8?usp... :
PS2, Line 14: 	assert(pmif_arb);
            : 	pmif_arb->read(pmif_arb, slvid, reg, data);
Please follow other PMICs' read/write semantic.

```
u16 data = 0;
assert(pmif_arb);
pmif_arb->read(pmif_arb, slvid, reg, &data);

return data
```

File src/soc/mediatek/common/mt6316.c:

https://review.coreboot.org/c/coreboot/+/85630/comment/909f11af_dfd702f8?usp... :
PS3, Line 164: 0x222
Is the mask correct ? Doesn't `pmif_arb->write` send one byte per call ?

https://review.coreboot.org/c/coreboot/+/85630/comment/75f92109_663348cc?usp... :
PS3, Line 169: reg_val_6
We expect to read one byte back, right ?