rtlwifi: btcoexist: Add second part of BT coexistence routines for rtl8821ae

This code comes from the V062414 version of the drivers from Realtek.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: troy_tan@realsil.com.cn
Signed-off-by: John W. Linville <linville@tuxdriver.com>