wifi: rtw89: pci: add PCI generation information to pci_info for each chip

In order to reuse PCI initial and configuration flows, add struct
rtw89_pci_gen_def to abstract the differences between WiFi 6/7 generations.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231101072149.21997-2-pkshih@realtek.com