wifi: rtw88: Reset 8703b firmware before download

Sometimes 8703b firmware is still active from previous use when the
driver needs to download the firmware during MAC activation. Reset it
in that case.

Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Tested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Fiona Klute <fiona.klute@gmx.de>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240311103735.615541-9-fiona.klute@gmx.de