rtlwifi: btcoexist: Fix interference between rtl8723be and Bluetooth

During usage of the new Bluetooth driver for Realtek devices, it was found
that BT scans were inhibited for the RTL8723BE when wireless was active. The
exact cause of this interference is not known yet, but a satisfactory work
around has been found that does not seem to have any visible side effects.

Signed-off-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Shao Fu <shaofu@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>