avcodec/mediacodecdec: fix return EAGAIN after EOF

Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>
(cherry picked from commit f27fce0c0c)

libavcodec/mediacodecdec_common.c

@@ -804,6 +804,8 @@ int ff_mediacodec_dec_receive(AVCodecContext *avctx, MediaCodecDecContext *s,
         return AVERROR_EXTERNAL;
     }
 
+    if (s->draining && s->eos)
+        return AVERROR_EOF;
     return AVERROR(EAGAIN);
 }