Bluetooth: hci_sync: fix BR/EDR wakeup bug

when Bluetooth set the event mask and enter suspend, the controller
has hci mode change event coming, it cause controller can not enter
sleep mode. so it should to set the hci mode change event mask before
enter suspend.

Signed-off-by: clancy shang <clancy.shang@quectel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>