[Mellanox] Update pcie.yaml for SN6810_LD hardware and SimX platforms to reflect the actual PCIe topology

[Junchao-Mellanox]

Why I did it

• The existing pcie.yaml did not match the current SN6810_LD PCIe topology.
• Outdated or incorrect entries could cause PCIe health checks to fail at boot or report false alarms.
• SimX should use the same expected PCIe layout as hardware so validation and bring-up behave consistently across both environments.

Work item tracking

• Microsoft ADO (number only):

How I did it

• Refreshed pcie.yaml on both SN6810_LD platforms based on the actual PCIe enumeration from the target system.
• Removed stale entries and corrected bus/device assignments to match the current hardware design.
• Ensured both hardware and SimX platform directories share a consistent PCIe baseline.

How to verify it

• Boot SN6810_LD hardware and confirm PCIe check passes without errors
• Boot SN6810_LD SimX and confirm PCIe check passes without errors
• Verify pcieutil check (or equivalent PCIe validation) reports no missing or unexpected devices
  = Confirm no regression in platform bring-up or monitoring services

Which release branch to backport (provide reason below if selected)

• 202305
• 202311
• 202405
• 202411
• 202505
• 202511

Tested branch (Please provide the tested image version)

Description for the changelog

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[mssonicbld]

/azp run Azure.sonic-buildimage

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[mssonicbld]

/azp run Azure.sonic-buildimage

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