Bluetooth: host: Deleting PA sync before term callback

The PA sync is now "deleted" (i.e. flags reset) before
the terminated callback is called, so that is
possible to create PA sync in the callback. One flag
was already cleared before for this reason, but one
other flag is also required, so we just clear
everything now.

Signed-off-by: Emil Gydesen <emil_gydesen@bose.com>