DO NOT MERGE - audio policy service: fix possible memory overflow

Add limit on number of audio ports and patches requested by
listaudioPorts() and listAudioPatches().

Bug: 19261727.
Change-Id: I21dfdf11cf805734cc3b7b2a85762c5598f60580
(cherry picked from commit 1d670b11313250442455a22f1056ad649d607fb2)
