Bluetooth: BAP: Broadcast source reconfig with subgroups

Modify the bt_bap_broadcast_source_reconfig to use the same
parameter struct as bt_bap_broadcast_source_create so that
the two are more similar, since they both set the same values.

This allow for full control of which subgroups and stream
are updated.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>