Change in coreboot[master]: soc/mediatek: Add timestamp to measure PERST# time

[Jianjun Wang (Code Review)]

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

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

https://review.coreboot.org/c/coreboot/+/62933

to look at the new patch set (#3).

Change subject: soc/mediatek: Add timestamp to measure PERST# time
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soc/mediatek: Add timestamp to measure PERST# time

Add timestamp support to measure the assertion time of PERST#.

TEST=Build pass and boot up to kernel successfully via SSD on Dojo
board, here is the measured PERST# time:
[DEBUG]  mtk_pcie_domain_enable: 432517 us elapsed since assert PERST#
[INFO ]  mtk_pcie_domain_enable: PCIe link up success (17 tries)

And the SSD information in boot log is as follows:
 == NVME IDENTIFY CONTROLLER DATA ==
    PCI VID   : 0x15b7
    PCI SSVID : 0x15b7
    SN        : 21517J440114
    MN        : WDC PC SN530 SDBPTPZ-256G-1006
    RAB       : 0x4
    AERL      : 0x7
    SQES      : 0x66
    CQES      : 0x44
    NN        : 0x1
Identified NVMe model WDC PC SN530 SDBPTPZ-256G-1006

BUG=b:178565024
BRANCH=cherry

Signed-off-by: Jianjun Wang 
Change-Id: Ie2b7b6174abdf951af5796ab5ed141c45f32fc71
---
M src/soc/mediatek/common/Kconfig
M src/soc/mediatek/common/pcie.c
M src/soc/mediatek/mt8195/pcie.c
3 files changed, 20 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/33/62933/3