mb/google/cherry: Complete PCIe reset in romstage

De-assert PERST# at romstage to reduce the waiting time in ramstage.

Before
```
[INFO ]  wait_perst_done: PCIe early PERST# de-assertion is not done,
de-assert PERST# now
[INFO ]  mtk_pcie_domain_enable: PCIe link up success (47 tries)
```
After
```
[INFO ]  wait_perst_done: PCIe early PERST# de-assertion is not done,
de-assert PERST# now
[DEBUG]  wait_perst_asserted: 457568 us elapsed since assert PERST#
[DEBUG]  wait_perst_done: 163413 us elapsed since de-assert PERST#
[INFO ]  mtk_pcie_domain_enable: PCIe link up success (1 tries)
```

BUG=none
TEST=boot from NVMe

Change-Id: I3a73bd574ae8f9f4e624846ce8b901a7d2209e78
Signed-off-by: Yidi Lin <yidilin@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84118
Reviewed-by: Jianjun Wang <jianjun.wang@mediatek.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>

0 files changed, 0 insertions, 0 deletions