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

[Raul Rangel (Code Review)]

Attention is currently required from: Jason Glenesk, Furquan Shaikh, Marshall Dawson, Paul Menzel, Tim Wawrzynczak, Karthik Ramasubramanian, Felix Held.
Raul Rangel 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)

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

https://review.coreboot.org/c/coreboot/+/54966/comment/02cf4c4c_eae27e8d 
PS1, Line 206: PXSX
> @Tim: Once the change lands, you will have to update Intel platforms to expose the _DSD property und […]

The change shouldn't affect functionality. It would just be a cleanup if you wanted to rename the PSXS acpi node.

https://review.coreboot.org/c/coreboot/+/54966/comment/616c8ced_e996e49e 
PS1, Line 210: pci_dev_read_resources
> > So is the driver good as is then? […]

I'll do that and push up a change.