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, 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)

Commit Message:

https://review.coreboot.org/c/coreboot/+/54966/comment/05ecccba_0085b8cb 
PS1, Line 9:  I decided
           : to copy and modify it because the Intel driver has a lot of Intel
           : specific code.
> > So this is where I grew uncomfortable. […]

I filed b/189834892 to track the `GL9755` issue.

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

https://review.coreboot.org/c/coreboot/+/54966/comment/e98c7b77_12d76367 
PS1, Line 210: pci_dev_read_resources
> > I wasn't a fan of the fake device because it made it difficult to understand.  […]

It sounds like we need some type of composition. How about something like this?

struct drivers_pcie_rtd3_device_config {
    DEVTREE_CONST struct device *target;
}

---

device ref gpp_bridge_3 on
    device pci 00.0 alias nvme on end

# Required so the NVMe gets placed into D3 when entering S0i3.
    chip drivers/pcie/rtd3/device
    	use nvme as target
    	device generic 0 on end
    end
end # NVMe

---

acpigen_write_device(acpi_device_path(config->target));

---

I think this makes it clear that the rtd3 driver is writing an ACPI node for the PCI device. It allows us to remove the hard coded `acpigen_write_ADR(0);` as well.