ffmpeg: remove unapplicable patch

package/ffmpeg/0001-ffmpeg-pthreads.patch

@@ -1,34 +0,0 @@
-From patchwork Wed Oct 25 13:32:36 2017
-Content-Type: text/plain; charset="utf-8"
-MIME-Version: 1.0
-Content-Transfer-Encoding: 7bit
-Subject: [FFmpeg-devel] configure: v4l2_m2m depends on pthreads
-From: Mark Thompson <sw@jkqxz.net>
-X-Patchwork-Id: 5688
-Message-Id: <27e5b360-1210-d550-c8de-a761f8e9f326@jkqxz.net>
-To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
-Date: Wed, 25 Oct 2017 14:32:36 +0100
-
-Fixes build with --disable-pthreads.
-
-Downloaded from upstream patchworks:
-https://patchwork.ffmpeg.org/patch/5688/
-
-Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
----
- configure | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/configure b/configure
-index c86e578..76523c8 100755
---- a/configure
-+++ b/configure
-@@ -2780,7 +2780,7 @@ omx_rpi_select="omx"
- qsvdec_select="qsv"
- qsvenc_select="qsv"
- vaapi_encode_deps="vaapi"
--v4l2_m2m_deps_any="linux_videodev2_h"
-+v4l2_m2m_deps="linux_videodev2_h pthreads"
- 
- hwupload_cuda_filter_deps="cuda"
- scale_npp_filter_deps="cuda libnpp"