Bluetooth: hci_sync: Don't double print name in add/remove adv_monitor

The hci_add_adv_monitor() hci_remove_adv_monitor() functions call
bt_dev_dbg() to print some debug statements. The bt_dev_dbg() macro
automatically adds in the device's name. That means that we shouldn't
include the name in the bt_dev_dbg() calls.

Suggested-by: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>