rtw89: pci: refine pci pre_init function

The pre_init is used to initialize partial PCI function during PCI probe.
It doesn't need to initialize all functions, so probe can be faster.

Signed-off-by: Chia-Yuan Li <leo.li@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220325060055.58482-4-pkshih@realtek.com