Change in coreboot[master]: soc/mediatek/mt8195: Add driver to configure PCIe

[Jianjun Wang (Code Review)]

Attention is currently required from: Hung-Te Lin, Paul Menzel, Angel Pons, Yu-Ping Wu.
Hello Hung-Te Lin, build bot (Jenkins), Yu-Ping Wu,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/56792

to look at the new patch set (#12).

Change subject: soc/mediatek/mt8195: Add driver to configure PCIe
......................................................................

soc/mediatek/mt8195: Add driver to configure PCIe

Add a new function 'mtk_pcie_pre_init' to assert the PCIe reset at early
stage to reduce the impact of 100ms delay.

TEST=Build pass and boot up to kernel successfully via SSD on Cherry
board, here is the SSD information in boot log:
 == NVME IDENTIFY CONTROLLER DATA ==
    PCI VID   : 0x1987
    PCI SSVID : 0x1987
    SN        : 28F40713077B0012602
    MN        : Phison ESE1A043-X28
    RAB       : 0x1
    AERL      : 0x3
    SQES      : 0x66
    CQES      : 0x44
    NN        : 0x1
Identified NVMe model Phison ESE1A043-X28

BUG=b:178565024

Signed-off-by: Jianjun Wang 
Change-Id: If6799c53b03a33be91157ea088d829beb4272976
---
M src/soc/mediatek/mt8195/Makefile.inc
A src/soc/mediatek/mt8195/include/soc/pcie.h
A src/soc/mediatek/mt8195/pcie.c
3 files changed, 112 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/92/56792/12