opensles: simplify error handling
opensles: simplify error handling

Instead of busy waiting and retrying, buffer packets and wait for the next
pf_play() call to write them to the sound card.
We now have 2 linked lists:
    - packets not accepted yet by Enqueue()
    - packets accepted by Enqueue(), not yet written to hardware, and
    waiting to be released in PlayedCallback()

xkfz007/vlc,jomanmuk/vlc-2.2,shyamalschandra/vlc,xkfz007/vlc,vlc-mirror/vlc,shyamalschandra/vlc,shyamalschandra/vlc,krichter722/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,jomanmuk/vlc-2.1,xkfz007/vlc,vlc-mirror/vlc,shyamalschandra/vlc,krichter722/vlc,vlc-mirror/vlc-2.1,xkfz007/vlc,vlc-mirror/vlc,vlc-mirror/vlc,krichter722/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc,krichter722/vlc,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,jomanmuk/vlc-2.1,xkfz007/vlc,krichter722/vlc,jomanmuk/vlc-2.1,shyamalschandra/vlc,jomanmuk/vlc-2.1,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,vlc-mirror/vlc-2.1,xkfz007/vlc,jomanmuk/vlc-2.2,shyamalschandra/vlc,krichter722/vlc,krichter722/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,vlc-mirror/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc-2.1,vlc-mirror/vlc,xkfz007/vlc,vlc-mirror/vlc-2.1