GFX: add config which to prefer H264 vs RFX #2133

Job	Run time
cppcheck	18m 13s
code formatting check	25s
min features with gcc	2m 52s
min features with g++	2m 31s
min features with clang	3m 3s
max features with gcc	3m 40s
max features with g++	2m 22s
max features with clang	3m 26s
max features with clang and AddressSanitized	2m 48s
max features with gcc and DEBUG	2m 18s
max features with gcc for 32-bit arch (legacy OS)	2m 5s
max features with g++ for 32-bit arch (legacy OS)	1m 28s
max features with clang for 32-bit arch (legacy OS)	1m 50s
	47m 1s

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