Claude review: PCI/TPH: expose the enabled TPH requester type

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

A small, clean accessor to avoid drivers reaching into `pci_dev` internals.

**Observation: EXPORT_SYMBOL vs EXPORT_SYMBOL_GPL**

```c
u8 pcie_tph_enabled_req_type(struct pci_dev *pdev)
{
	return pdev->tph_req_type;
}
EXPORT_SYMBOL(pcie_tph_enabled_req_type);
```

The existing `pcie_tph_get_st_table_loc` also uses plain `EXPORT_SYMBOL`, so this is consistent with the file's convention. However, many newer PCI subsystem exports use `EXPORT_SYMBOL_GPL`. The PCI maintainers may have a preference here — worth confirming, but not a blocker since the file is internally consistent.

**Stub return value:** The `!CONFIG_PCIE_TPH` stub returns `0`, which maps to `PCI_TPH_REQ_DISABLE`. This is correct — callers will see TPH as disabled, which is the safe default.

No other issues. Clean patch.

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Generated by Claude Code Patch Reviewer