wifi: rtw89: pci: use gen_def pointer to configure mac_{pre,post}_init and clear PCI ring index

Use gen_def pointer to call three WiFi 6 specific functions, and add _ax
suffix to them. Then, we will implement functions for WiFi 7 chips later.

The mac_{pre,post}_init are used to initialize PCI during doing MAC
initialization, and clear PCI ring index to make index consistent between
driver, firmware and hardware.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231101072149.21997-3-pkshih@realtek.com