lavc/videotoolbox: allow software fallback for all codecs

Apple disabled hardware decoding for some h264 files with certain
condition and now ffmpeg will error out for such inputs because the
software fallback is disabled. Allow software fallback for all codecs
instead of only for HEVC to workaround this as the error handling
outside ffmpeg would be harder. Allowing software fallback has no
measurable performance impact when the hardware decoder is not
overloaded.

debian/patches/0071-allow-vt-sw-decoder-for-every-codec.patch

@@ -0,0 +1,15 @@
+Index: FFmpeg/libavcodec/videotoolbox.c
+===================================================================
+--- FFmpeg.orig/libavcodec/videotoolbox.c
++++ FFmpeg/libavcodec/videotoolbox.c
+@@ -812,9 +812,7 @@ static CFDictionaryRef videotoolbox_deco
+                                                                    &kCFTypeDictionaryValueCallBacks);
+
+     CFDictionarySetValue(config_info,
+-                         codec_type == kCMVideoCodecType_HEVC ?
+-                            kVTVideoDecoderSpecification_EnableHardwareAcceleratedVideoDecoder :
+-                            kVTVideoDecoderSpecification_RequireHardwareAcceleratedVideoDecoder,
++                         kVTVideoDecoderSpecification_EnableHardwareAcceleratedVideoDecoder,
+                          kCFBooleanTrue);
+
+     avc_info = CFDictionaryCreateMutable(kCFAllocatorDefault,