rtlwifi: btcoex: 23b 2ant: let bt transmit when hw initialisation done

During hw initialisation, wifi may be ready after bt has already been
ready, which causes bt to act abnormally. To avoid this, set GNT_BT to
high during hw init.

Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Cc: Stable <stable@vger.kernel.org>
Cc: Pkshih <pkshih@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>