The rtlwifi driver comes with a number of PCI related defines that are
unused and many would be provided by PCI core anyway if they'd be
needed again.

Similarly, the struct rtl_pci_capabilities_header is unused and no
driver should come up their own way to access PCI Capabilities anyway.

Remove the unused/duplicated PCI related defines and struct.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231124084725.12738-10-ilpo.jarvinen@linux.intel.com