[pcied] Honour PCIE_DETACH_INFO on platforms that are not smartswitches

从 sonic-pcied/scripts/pcied 开始，检查第 109 行附近对 PCIE_DETACH_INFO 的无条件设置，以及第 211-213 行附近仅针对 smartswitch 的处理。跟踪 detached bus_info 如何影响 poll result、err 和 PCIE_DEVICES|status。完成的标准是：有意分离的设备在非 smartswitch 平台上得到正确处理，同时不会让 status 保持为 FAILED。

pcied only consults the PCIE_DETACH_INFO table when the platform is a smartswitch:

https://github.com/sonic-net/sonic-platform-daemons/blob/a9d71d7218e72423b3b993c39cfb07f1cdac8705/sonic-pcied/scripts/pcied#L211-L213

On anything else device_info.is_smartswitch() is False, so the table is never read and a device that has been deliberately detached is reported as missing on every poll:

pcied: PCIe Device: <name> Not Found

err is non-zero as a result, so PCIE_DEVICES|status in STATE_DB stays FAILED for as long as the device is detached, which in turn trips anything watching that field (e.g. loganalyzers in sonic-mgmt tests).

Nothing about the table is smartswitch-specific. pcied creates it unconditionally at startup:

https://github.com/sonic-net/sonic-platform-daemons/blob/a9d71d7218e72423b3b993c39cfb07f1cdac8705/sonic-pcied/scripts/pcied#L109

and its contract is just "this bus_info is expected to be absent right now". Smartswitches are simply the first consumer; a fixed-form switch that detaches a PCIe device to upgrade it in service (an FPGA or a retimer, say) has exactly the same need and no way to express it.

pcied should honour PCIE_DETACH_INFO regardless of platform type.