wifi: rtw89: add wait/completion for abort scan

When aborting scan, wait until FW is done to keep both states aligned.
This prevents driver modifying channel then gets overwritten by FW.

Signed-off-by: Po-Hao Huang <phhuang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240119081501.25223-7-pkshih@realtek.com