fix h264 by adding ffmpeg_branding #826

Job	Run time
Build (x86_64-pc-windows-msvc)	1m 21s
Build (aarch64-pc-windows-msvc)	1m 18s
Build (x86_64-apple-darwin)	1m 37s
Build (aarch64-apple-darwin)	1m 35s
Build (aarch64-apple-ios)	1m 37s
Build (aarch64-apple-ios-sim)	1m 33s
Build (x86_64-unknown-linux-gnu)	1m 32s
Build (aarch64-unknown-linux-gnu)	1m 11s
Build (aarch64-linux-android)	3m 11s
Build (armv7-linux-androideabi)	1m 34s
Build (x86_64-linux-android)	1m 33s
	18m 2s

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