Change in coreboot[master]: drivers/pcie/rtd3/device: Add PCIe RTD3 driver

[Furquan Shaikh (Code Review)]

Attention is currently required from: Jason Glenesk, Raul Rangel, Marshall Dawson, Tim Wawrzynczak, Karthik Ramasubramanian, Felix Held.
Furquan Shaikh has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/54966 )

Change subject: drivers/pcie/rtd3/device: Add PCIe RTD3 driver
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Patch Set 4:

(2 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/54966/comment/1952b91a_f4eda5f8 
PS1, Line 9:  I decided
           : to copy and modify it because the Intel driver has a lot of Intel
           : specific code.
> I filed b/189834892 to track the `GL9755` issue.

Thanks Raul!

File src/soc/amd/common/block/rtd3/rtd3.c:

https://review.coreboot.org/c/coreboot/+/54966/comment/4d5018a6_57b70bc1 
PS1, Line 210: pci_dev_read_resources
> It sounds like we need some type of composition. How about something like this? […]

That seems okay to me. Tim?