Change in coreboot[master]: sc7280: Add PCIe RC driver in Coreboot

[Ravi kumar (Code Review)]

Attention is currently required from: Shelley Chen, Ravi kumar, Furquan Shaikh, Julius Werner, mturney mturney.
Hello Shelley Chen, build bot (Jenkins), Julius Werner, Prasad Malisetty, mturney mturney,

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

https://review.coreboot.org/c/coreboot/+/53902

to look at the new patch set (#55).

Change subject: sc7280: Add PCIe RC driver in Coreboot
......................................................................

sc7280: Add PCIe RC driver in Coreboot

In coreboot ram stage, PCIe root complex driver initialize
the PCIe core, QMP PHY and does the bus enumeration.
Upon successful detection of EP(NVMe), PCIe RC driver
allocates the resources and set the configuration parameters.

Below are the changes added.
    (a) PCIe Core reset, init, link training.
    (b) Bus enumeration and resource allocation
    (c) QMP PHY 3x2 initialization

To enable NVMe LDO's, need to set gpio19 pin in SKU1
and gpio51 in SKU2.

BUG=b:182963902
TEST=Validated on qualcomm sc7280 development board

Change-Id: Iccf60aa56541f5230fa9c3f821d7709615c36631
Signed-off-by: Prasad Malisetty 
---
M src/mainboard/google/herobrine/mainboard.c
M src/soc/qualcomm/sc7280/Makefile.inc
M src/soc/qualcomm/sc7280/include/soc/addressmap.h
A src/soc/qualcomm/sc7280/include/soc/pcie.h
A src/soc/qualcomm/sc7280/include/soc/qcom_qmp_phy.h
A src/soc/qualcomm/sc7280/pcie_host.c
6 files changed, 1,693 insertions(+), 2 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/02/53902/55