Change in coreboot[master]: soc/intel/common/block/pcie/rtd3: Add PM methods to the device.

[Cliff Huang (Code Review)]

Attention is currently required from: Lance Zhao, Anil Kumar K, Selma Bensaid, Tim Wawrzynczak, Paul Menzel, Thejaswani Putta, Patrick Rudolph.
Cliff Huang has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/61352 )

Change subject: soc/intel/common/block/pcie/rtd3: Add PM methods to the device.
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Patch Set 1:

(1 comment)

File src/soc/intel/common/block/pcie/rtd3/chip.h:

https://review.coreboot.org/c/coreboot/+/61352/comment/5f0b152f_5350c758 
PS1, Line 53: ext_pm_support
> Yes. https://review.coreboot.org/c/coreboot/+/61354. […]

Hi Tim,
Since this header is not exposed to the device code, I couldn't find a way to inform the device what methods has been exported and available to the device via enum. However, I am adding this table as comments.

/*
     * Provides L23, modPHY gating, source clock enabling methods to the device
     * connected root port, mainly used in the device ACPI methods such as reset.
     * The methods to export are following this table:
     *-----------------------------------------------------------------------------------*
     | ext_pm_support | disable_l123 | srcclk_pin |   rp_type   |     exppoted methods   |
     *----------------+--------------+------------+-------------+------------------------*
     |     false      |       -      |     -      |      -      | None                   |
     |     true       |      true    |     =0     | PCIE_RP_CPU | None                   |
     |     true       |      true    |     =0     | PCIE_RP_PCH | SRCK                   |
     |     true       |      true    |     >0     | PCIE_RP_CPU | PSD0                   |
     |     true       |      true    |     >0     | PCIE_RP_PCH | PSD0, SRCK             |
     |     true       |      false   |     =0     | PCIE_RP_CPU | L23D, LD23             |
     |     true       |      false   |     =0     | PCIE_RP_PCH | L23D, LD23, SRCK       |
     |     true       |      false   |     >0     | PCIE_RP_CPU | L23D, LD23, PSD0       |
     |     true       |      false   |     >0     | PCIE_RP_PCH | L23D, LD23, PSD0, SRCK |
     *-----------------------------------------------------------------------------------*
     */
    Furthermore, CondRefof() will be used in the device code for the methods prior to calling How about it?