rtw88: coex: fix BT performance drop during initial/power-on step

Force set the coexistence to BT high priority during
WLAN initial/power-on step. Since the duration the related setting
may be not ready yet.

The score board is not related to scan when initialing, remove the scan
parameter.

Signed-off-by: Ching-Te Ku <ku920601@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201112031430.4846-9-pkshih@realtek.com