wifi: rtlwifi: remove misused flag from HAL data

Always rely on 'driver_is_goingto_unload' of 'struct rtl_hal'
and remove (presumably misused) 'driver_going2unload' from it.

Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230605100700.111644-1-dmantipov@yandex.ru