avcodec/mediacodecdec: use ff_hevc_ps_uninit()

Fixes memleaks.

Signed-off-by: James Almer <jamrial@gmail.com>
(cherry picked from commit 782e066e3e)

libavcodec/mediacodecdec.c

@@ -256,6 +256,8 @@ static int hevc_set_extradata(AVCodecContext *avctx, FFAMediaFormat *format)
     }
 
 done:
+    ff_hevc_ps_uninit(&ps);
+
     av_freep(&vps_data);
     av_freep(&sps_data);
     av_freep(&pps_data);