mediacodec: fix deprecated calls if API >= 21
mediacodec: fix deprecated calls if API >= 21

Use getInputBuffer and getOutputBuffer instead of getInputBuffers and
getOutputBuffers.

see http://developer.android.com/reference/android/media/MediaCodec.html

Signed-off-by: Jean-Baptiste Kempf <7b85a41a628204b76aba4326273a3ccc74bd009a@videolan.org>

krichter722/vlc,krichter722/vlc,shyamalschandra/vlc,xkfz007/vlc,shyamalschandra/vlc,xkfz007/vlc,shyamalschandra/vlc,xkfz007/vlc,vlc-mirror/vlc,shyamalschandra/vlc,krichter722/vlc,xkfz007/vlc,krichter722/vlc,shyamalschandra/vlc,vlc-mirror/vlc,shyamalschandra/vlc,krichter722/vlc,vlc-mirror/vlc,vlc-mirror/vlc,vlc-mirror/vlc,xkfz007/vlc,xkfz007/vlc,vlc-mirror/vlc,krichter722/vlc,vlc-mirror/vlc,xkfz007/vlc,shyamalschandra/vlc,krichter722/vlc