ffmpeg: add upstream patch

Signed-off-by: Stephan Raue <stephan@openelec.tv>

packages/multimedia/ffmpeg/patches/ffmpeg-2.8-upstream.patch

@@ -0,0 +1,23 @@
+From 101dcdc12659e7fc2ddc1393992e2b431e2c4da1 Mon Sep 17 00:00:00 2001
+From: Hendrik Leppkes <h.leppkes@gmail.com>
+Date: Fri, 22 Jan 2016 13:50:42 +0100
+Subject: [PATCH] dxva2_h264: fix reference field marking in long slice struct
+
+Fixes artifacts in interlaced decoding on old Intel GPUs.
+---
+ libavcodec/dxva2_h264.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/libavcodec/dxva2_h264.c b/libavcodec/dxva2_h264.c
+index eb5ecd1..242a79e 100644
+--- a/libavcodec/dxva2_h264.c
++++ b/libavcodec/dxva2_h264.c
+@@ -248,7 +248,7 @@ static void fill_slice_long(AVCodecContext *avctx, DXVA_Slice_H264_Long *slice,
+                 else
+                     index = get_refpic_index(pp, ff_dxva2_get_surface_index(avctx, ctx, r->f));
+                 fill_picture_entry(&slice->RefPicList[list][i], index,
+-                                   r->reference == PICT_BOTTOM_FIELD);
++                                   sl->ref_list[list][i].reference == PICT_BOTTOM_FIELD);
+                 for (plane = 0; plane < 3; plane++) {
+                     int w, o;
+                     if (plane == 0 && sl->luma_weight_flag[list]) {